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The trap states at both the upper and bottom interfaces of perovskite layers significantly impact non‐radiative carrier recombination. The widely used solvent‐based passivation methods result in the disordered distribution of surface components, posing challenges for the commercial application of large‐area perovskite solar cells (PSCs). To address this issue, a novel NH3 gas‐assisted all‐inorganic dual‐interfaces passivation strategy is proposed. Through the gas treatment of the perovskite surface, NH3 molecules significantly enhanced the iodine vacancy formation energy (1.54 eV) and bonded with uncoordinated Pb2+ to achieve non‐destructive passivation. Meanwhile, the reduction of the film defect states is accompanied by a decrease in the work function, which promotes carrier transport between the interface. Further, a stable passivation layer is constructed to manage the bottom interfacial defects using inorganic potassium tripolyphosphate (PT), whose ─P═O group effectively mitigated the charged defects and lowered the carrier transport barriers and nucleation barriers of PVK, while the gradient distribution of K+ improved the crystalline quality of PVK film. Based on the dual‐interface synergistic effect, the optimal MA‐contained PSCs with an effective area of 0.1 cm2 achieved an efficiency of 24.51% and can maintain 90% of the initial value after aging (10−20% RH and 20 °C) for 2000 h. [ABSTRACT FROM AUTHOR]

Introduction of fluorescent down‐conversion layer inside perovskite solar cells (PSCs) can highly improve the ultraviolet response of the devices and the light stability. However, such a device is usually confronted with the problem of inter‐diffusion with the perovskite absorber layer, which severely limits its further development. To address this problem, herein, this work employs an interfacial dual electron transport layers (ETLs) strategy, sandwiching Cd‐CsPbCl3:Mn2+ luminescent quantum dots within gap of the ETLs, which not only reduces the interface energy level offset, but also improves the nucleation and crystallization kinetics of perovskite films and prevents their diffusion to the perovskite absorber layer. As a result, the efficient synergy effect effectively elevates both the open‐circuit voltage and fill factor of the PSCs, reaching maximum values of 1.181 V and 81.14%, respectively, finally delivering progressively increased device power conversion efficiency (PCE) of 24.32% with significantly improved light stability. To further improve the ultraviolet response, this work further adopts the strategy of dual fluorescent conversion layers inside and outside the PSCs, and finally obtains PCE of 24.63%, which is the best for various luminescent conversion cells. This work opens a new door for the development of efficient and stable photoluminescence conversion PSCs. [ABSTRACT FROM AUTHOR]

Introducing excess PbI2 has proven to be an effective in situ passivation strategy for enhancing efficiency of perovskite solar cells (PSCs). Nevertheless, the photoinstability and hysteresis are still tough issues owing to the photolysis nature of PbI2. Moreover, the humidity‐related degradation of perovskite films is also a difficult territory to cover in such an in situ passivation strategy. Herein, a synergistic strategy is reported via initiatively inducing vertical graded PbI2 distribution (GPD) in the whole perovskite film and capping a cis‐Ru(H2dcbpy)(dnbpy)(NCS)2 (Z907) internal encapsulation (IE) layer on the surface to ameliorate the above issues. The GPD design can enhance luminescence, prolong carrier lifetimes, ascertaining the improvement of efficiency and elimination of photoinstability in the PSCs. Besides, the introduced IE layer not only can promote the moisture and thermal resistance, but also inhibit Pb leakage and ion migration in the PSCs. Through the synergetic regulations, the resultant PSCs exhibit an impressive open circuit voltage (VOC) of 1.253 V, fill factor of 81.25%, and power conversion efficiency (PCE) of 24.28%. Moreover, the PSCs maintain 91% of its initial PCE at relative humidity of 85% after 500 h aging and 94% under continuous heating at 85 °C after 750 h aging. [ABSTRACT FROM AUTHOR]

The defect passivation and interface energetics‐modification between perovskite and transport layers are significant for the further improvement of efficiency and stability of perovskite solar cells (PSCs). Here, a double‐layer modification engineering strategy is employed by different functionalized natural vitamins into the electron transport layer and perovskite, respectively. Considering the different role of each functional layer in PSCs, the vitamin C (VC) with high conductivity is introduced into SnO2, showing electron mobility enhancement, an interface energy‐levels offsets reduction, and enhanced interfacial charge transfer. Meanwhile, antioxidant vitamin D2 (VD2) with multiple passivating functional groups is introduced into the perovskite bulk to moderately tailor its intrinsic characteristics. The surface energetics of perovskite are changed from n‐type to p‐type, the thickness of the p‐type perovskite is 80 nm, thus the spontaneous n–p homojunction is formed in perovskite caused by VD2, which increases the built‐in electric field and the efficiency of perovskite hole extraction. The synergistic effect of VC and VD2 better heightens the charge extraction efficiency and achieves charge‐carrier transport balance in PSCs. The optimum device achieves a power conversion efficiency of 24.20% and a fill factor of 81.01% with negligible hysteresis. This efficiency is among the best PSCs employing natural molecules reported so far. [ABSTRACT FROM AUTHOR]

The open‐circuit voltage (VOC) and fill factor (FF) of perovskite solar cells (PSCs) are detrimentally weakened by carrier loss at the perovskite/charge transport layers (CTLs) interfaces. Herein, a dual interfacial modification strategy via placing Nb2CTx nanosheets with tailored optoelectrical properties induced by manipulating surface terminal groups at both perovskite/CTLs interfaces is employed. Such tactics not only concurrently implement carrier mobility enhancement of CTLs and interface energy‐levels offsets reduction. More importantly, electrical simulation indicates that the Nb2CTx with O terminal groups located at grain boundaries of the perovskite layer, can more efficiently conduct hole current to the hole transport layer, therefore achieving charge‐carrier transport balance in device. As a result, the synergy effect effectively elevates both the VOC and FF of the cells, reaching maximum values of 1.253 V and 81.07%, respectively, finally delivering progressively increased device power conversion efficiency (PCE) of 24.11% with negligible hysteresis. This PCE value ranks in the highest values to date for PSCs employing MXenes materials. Moreover, the optimized devices show better thermal and light stability than control devices. This work demonstrates a simple and effective dual interfacial modification method utilizing Nb2CTx for photovoltaic field, involving photodetectors, light‐emitting diodes, sensors, etc. [ABSTRACT FROM AUTHOR]

The passivation effect of inorganic perovskite quantum dots (PQDs) is a promising method to attain outstanding performance in perovskite solar cells (PSCs), which has ignited widespread interest recently. Lanthanides (Ln) doped PQDs demonstrate unique properties, but nevertheless, are not explored in PSCs. In this work, four kinds of Ln3+ doped CsPbBrCl2 PQDs (Ln3+ = Yb3+, Ce3+, Eu3+, Sm3+) are firstly introduced into PSCs, which displays the synergistic effect of composition engineering and defect engineering. The results indicate that the introduction of CsPbBrCl2: Ln3+ can not only improve the crystallinity and passivate the intrinsic and surface defects of the MAPbI3 layer through ion and ligand passivation, but also form a stronger LnI bond than PbI, adjust work function (WF), and optimize band alignments. CsPbBrCl2:Sm3+ PQDs possess the best performance and exhibit remarkable promotions of open‐circuit voltage (Voc) from 1.13 to 1.20 V and power conversion efficiency from 18.54% to 22.52%. The humid‐resist, thermal‐resist abilities, and the long‐term stability of PSCs are energetically improved due to enhanced structure stability by Sm3+ doping and the hydrophobic characteristic. The strategy of Ln3+ doped PQDs applied to PSCs provide an approach to achieve high‐performance PSCs. [ABSTRACT FROM AUTHOR]

Extending near‐infrared (NIR) spectral response and increasing ultraviolet utilization is still a challenge in the context of improving power conversion efficiency (PCE) for perovskite solar cells (PSCs). In this work, to extend NIR light‐harvesting of PSCs, a novel COTIC‐4F: PC61BM: PTB7‐Th ternary organic bulk‐heterojunction together with Au nanotriangles is integrated on the PSCs. The NIR spectral response is thus extended to 1100 nm. In fact, the COTIC‐4F: PC61BM: PTB7‐Th layer enables multi‐functional effects, which can serve as electron transport, trap passivation, and moisture barrier layer in addition to NIR light harvesting. For increasing UV utilization, CsPbCl3:Yb3+, Ce3+, Cr3+ nanophosphors with photoluminescent quantum yield close to 200% are fabricated, which demonstrate excellent down‐conversion ability. Then, CsPbCl3: Yb3+, Ce3+, Cr3+/polymethylmethacrylate composite films are self‐assembled on a hybrid device, resulting in a 6.2% relative enhancement of short circuit current density. After simultaneously improving the NIR and UV spectral response of device, the PCE is increased significantly from 20.52% to 23.40% and the Jsc is increased from 21.79 to 25.96 mA cm−2, representing one of the highest PCE and maximum Jsc enhancements in the reported inverted hybrid organic/PSCs. This work represents an effective and general strategy for obtaining efficient and stable PSC devices with extremely broad spectral responses. [ABSTRACT FROM AUTHOR]

Organolead halide hybrid perovskite solar cells (PSCs) have become a shining star in the renewable devices field due to the sharp growth of power conversion efficiency; however, interfacial recombination and carrier‐extraction losses at heterointerfaces between the perovskite active layer and the carrier transport layers remain the two main obstacles to further improve the power conversion efficiency. Here, novel field‐effect passivation has been successfully induced to effectively suppress the interfacial recombination and improve interfacial charge transfer by incorporating interfacial polarization via inserting a high work function interlayer between perovskite and holes transport layer. The charge dynamics within the device and the mechanism of the field‐effect passivation are elucidated in detail. The unique interfacial dipoles reinforce the built‐in field and prevent the photogenerated charges from recombining, resulting in power conversion efficiency up to 21.7% with negligible hysteresis. Furthermore, the hydrophobic interlayer also suppresses the perovskite decomposition by preventing the moisture penetration, thereby improving the humidity stability of the PSCs (>91% of the initial power conversion efficiency (PCE) after 30 d in 65 ± 5% humidity). Finally, several promising research perspectives based on field‐effect passivation are also suggested for further conversion efficiency improvements and photovoltaic applications. [ABSTRACT FROM AUTHOR]

Simultaneously modulating the optical and electrical properties of the hole transporting layer (HTL) plays a vital role in the performance of p-i-n perovskite solar cells (PSCs). Here, a negligible hysteresis inverted planar PSC with 17.30% power conversion efficiency was successfully fabricated by employing a thin and non-stoichiometric dopant-free nickel oxide (DF-NiO x) film as the HTL. The DF-NiO x film was formed by a radio frequency magnetron sputtering method. The Ni3+ content as well as the crystallization of the DF-NiO x thin films were tuned by regulating the post-annealing treatment, leading to enhanced optical transmittance and electrical conductivity. The optimized DF-NiO x films exhibit a high transmittance of more than 90%, appropriate conductivity, uniform surface morphology, and a better energy level match with the perovskite layer. This study not only highlights the importance of optimizing the Ni3+ content and crystallization for the formation of high-performance DF-NiO x HTLs, but also provides an excellent device platform for making large area high-performance PSCs and tandem solar cells. Image 1 [ABSTRACT FROM AUTHOR]

Inorganic-organic perovskites, such as CH 3 NH 3 PbX 3 (X = I, Br, Cl), is significant improvements in power conversion efficiencies, demonstrating the enormous potential of perovskite materials. Rapid extraction of photo-generated charge carriers from high-quality perovskite films is essential to achieve efficient perovskite solar cells (PSCs). Here, we devote to improving the charge-extraction ability of the electron transport layers (ETLs) and the crystallization of the perovskite layers by optimizing the ETLs' fabrication process. Insight into the impacts of ETLs architecture on the ETLs/perovskite hetero-interface properties and the quality of perovskite films are originally elucidated. The optimized ETLs increase the open-circuit voltage (V oc) of the MAPbI 3 -based PSCs by up to 100 mV, and the optimal device achieves V oc ∼ 1.13 V. Under the AM 1.5 simulated sunlight illumination, the optimized PSCs achieves an optimum PCE of 19.7% and maintains good stability after a storage time of 30 days with exposed to the ambient air environment. One of the key limitations of current PSCs performance is effectively solved by this simple optimization method and paves the way for further improve the efficiency through interface engineering. Image 1 • Crystallization of MAPbI 3 is improved by structural engineering the mesoporous TiO 2. • Unraveling the role of mesoporous TiO 2 structure for PSCs performance enhancement. • Photogenerated charge extraction has been boosted by the O-m-TiO 2. • MAPbI 3 -based PSCs achieve a high efficiency of 19.7%. [ABSTRACT FROM AUTHOR]

Efficient perovskite solar cells with ultra-thin absorber would be very attractive for semitransparent-, tandem-, and flexible-photovoltaic application. However, the absorber with ultra-thin thickness always cause extra optical losses due to the insufficient light-harvesting. Here, we try to stress this key factor by constructing textured substrates and appropriate control of recrystallization treatment for ultra-thin perovskite solar cells that synergizes the merits characters including good broad-band, enhanced light-trapping and excellent separation/collection of photo-generated charges. In particularly, the isopropanol (IPA) - assisted recrystallizing treatment enable to form pinholes free perovskite films on a high-aspect-ratio substrate, which relax the trade-off between the optical enhancements and electrical deteriorations. The perovskite solar cell exhibits an efficiency of 18.6% by using an only ∼200-nm MAPbI 3 as the absorber, which is a record efficiency for such thin-perovskite solar cells. We also exhibit the solar cells that shows the enhancement of daily generated power to 47.6% by using the crater-like architecture, as compared to traditional planar devices. The concurrent enhancement in optical and electrical performance for achieving high-efficiency perovskite solar cells with thin absorber demonstrated here makes a simple process promising for photoelectric device application. Image 1 • Quasi-omnidirectional perovskite solar cell with ultra-thin absorber has been prepared. • Efficient light trapping has achieved by employing crater-textured substrates. • Interface defects have been effectively eliminated by the proposed recrystallizing treatment. • A high efficiency of 18.6% have been achieved for ∼200 nm perovskite solar cells. [ABSTRACT FROM AUTHOR]

The interface defects and energy barrier between perovskite and electron transport layer (ETL) severely hinder the further improvement of the efficiency and stability of the perovskite solar cells (PSCs). Therefore, there is an urgent desire to develop multifunctional interface modulators to manage the interface between perovskite and ETL. Here, a multifunctional bottom-up double-layer interface modulation strategy is developed, that is, 2,2′-[[12,13-Bis(2-butyloctyl)− 12,13-dihydro-3,9-dinonylbisthieno[2'',3'':4′,5′]thieno[2′,3′:4,5]pyrrolo[3,2-e:2′,3′-g][2,1,3]benzothiadiazole-2,10-diyl]bis[methylidyne(5,6-chloro-3-oxo-1 H-indene-2,1(3 H)-diylidene)]]bis[propanedinitrile] (BTP-eC9) is combined in the SnO 2 /perovskite interface to achieve high efficiency and outstanding stability of PSCs. The BTP-eC9 can effectively prevent the detrimental contact between the FTO and perovskite and construct two electron transport paths by formatting the cascade energy level structure, which can eliminate the probability of carrier recombination and improve the interfacial carrier transfer. Chemically, BTP-eC9 can not only passivate the uncoordinated Sn ions, showing high conductivity and large photo-generated carrier transmission efficiency, but also can effectively passivate the underlying perovskite defects through a spontaneous bottom-up passivation process and improve the nucleation and crystallization kinetics of perovskite films. Based on the above efficient synergy, the power conversion efficiency (PCE) of up to 23.10% was obtained and it retains 90% of its original PCE after 8000 h in the ambient atmosphere without any encapsulation by the two-step method. In addition, the champion PCE of 23.75% with ultrahigh open-circuit voltage (V OC) of 1.25 V was achieved by the one-step method and this V OC is the highest value of a perovskite film with a band gap of approximately 1.60 eV, demonstrating the effectiveness and universality of this strategy. This research guides design methods of the ETL to raise the PCE of PSCs by interfacial engineering. [Display omitted] • The BTP-eC9 is designed as a multifunctional bottom-up interface modulation and combined in the SnO 2 /perovskite interface. • The BTP-eC9 can effectively prevent the detrimental contact between FTO and perovskite to improve the carrier transfer. • The BTP-eC9 can not only passivate the uncoordinated Sn ions, but also passivate the underlying perovskite defects. • PSCs retain 90% of its original PCE after 8000 h in the ambient atmosphere without encapsulation by the two-step method. • The double-layer interface optimization strategy provides an avenue for further improve the performance of PSCs. [ABSTRACT FROM AUTHOR]

Additive engineering is one of the most effective techniques for optimizing the performance of perovskite solar cells (PSCs). However, the previous research mainly focused on adopting this strategy to a single layer of the PSCs. In this work, a double-layer synergistic optimization approach is employed by simultaneously introducing functional black phosphorus quantum dots (BPQDs) into the electron transport layer (ETL) and perovskite layer. The BPQDs with superior conductivity is doped into SnO 2 ETL to effectively fill the electron traps and enhance electron mobility of SnO 2. Meanwhile, the 3-aminopropyltriethoxysilane-modified BPQDs (BPQDs@APTES) is introduced into the perovskite bulk to moderately tailor its intrinsic characteristics, and this synchronously facilitates the perovskite nucleation and growth, passivates defects and improves moisture-resistance of perovskite film. Taking advantage of the synergistic effects, efficient PSCs with power conversion efficiency of 22.85% with ultrahigh open-circuit voltage (V OC) of 1.22 V is demonstrated, this V OC value ranks in the highest values of perovskite film with a bandgap of ~ 1.60 eV. Additionally, the non-encapsulated BPQDs modified PSCs show better long time and humidity stability. In this work, a double-layer synergistic optimization strategy is demonstrated through incorporating functional black phosphorus quantum dots (BPQDs) into the SnO 2 and perovskite layer. Eventually, the perovskite solar cells (PSCs) with functional BPQDs modification achieve a champion efficiency of 22.85% with ultrahigh open-circuit voltage (V OC) (1.22 V). This work provides a route to design strategies within electron transport layer (ETL) and perovskite bulk to improve the performance of the PSCs. [Display omitted] • The BPQDs is designed as a bifunctional reagent and synchronously incorporated into the SnO2 and perovskite bulk. • The BPQDs can effectively fill the electron traps and passivate defect of SnO 2. • The BPQDs@APTES can facilitate perovskite growth, passivate defects and improve moisture-resistance of perovskite film. • High-efficiency (22.85%) PSCs with a VOC of 1.22 V are reported for a perovskite film having a bandgap of ~ 1.60 eV. • The double-layer synergistic optimization strategy provides an avenue for further improve the performance of PSCs. [ABSTRACT FROM AUTHOR]

Interfacial engineering strategy between the perovskite absorber and the charge transport layer play a vital role in highly efficient perovskite solar cells. Here, we propose an amorphous tungsten oxides/tin dioxide hybrid electron transport layer to effectively block holes through the pinholes and cracks of tin dioxide to indium tin oxide, resulting in promoting charge extraction and hindering electron-hole recombination process at the hetero-interface. Moreover, owing to the higher mobility of amorphous tungsten oxides and formation of cascade energy level sequence between amorphous tungsten oxides and tin dioxide, better electron transport is obtained compared with the traditional electron transport layer. The PSCs based on amorphous tungsten oxides/tin dioxide hybrid electron transport layer shows a better power conversion efficiency of 20.52% than the single tin dioxide electron transport layer. This study guides design strategies of the electron transport layer to enhance the efficiency of the perovskite solar cells by interfacial engineering. Moreover, the entire devices preparation process are finished at a temperature below 150 °C, promising great potential for the practical use in monolithic tandem devices and providing an avenue for the progress of flexible device. Image 1 • An efficient a-WO x /SnO 2 hybrid electron transport layer has been developed for PSCs. • The a-WO x /SnO 2 ETL create a cascade energy level to promote charge extraction. • PSCs based on a-WO x /SnO 2 hybrid electron transport achieved an efficiency of 20.52%. • Flexible PSCs with single a-WO x ETL obtained a relative high efficiency of 15.7%. [ABSTRACT FROM AUTHOR]

The breakthrough of organometal halide perovskite solar cells (PSCs) based on mesostructured composites is regarded as a viable member of next generation photovoltaics. In high efficiency PSCs, it is crucial to finely optimize the charge dynamics and optical properties matching between the perovskites and electron transporting materials to relax the trade‐off between the optical and electrical requirements. Here, a simple antipolar route with H2O as the additive is proposed to prepare hierarchical electron transporting layers to boost the efficiency of dopant‐free PSCs. The photovoltaic performance of the PSCs is enhanced owing to increased light‐scattering, improved Ostwald ripening, and photo‐generated electron extraction. Optimization of the H2O addition enables a valid power conversion efficiency of 19.9% (reverse scan: 20.02%) to be achieved. The device can retain more than 90% of its initial performance after storage in air more than 30 days. These results are inspiring in that they present that a mesoporous transporting layer could be easily re‐constructed to hierarchical architecture by the antipolar method to further improve the performance of PSCs. A simple antipolar route is proposed to prepare hierarchical electron transporting layers for boosting the efficiency of dopant‐free perovskite solar cells (PSCs). The photovoltaic performance of PSCs is enhanced owing to the enhanced light‐scattering, the improved Ostwald ripening process, and the promoted photo‐generated electron extraction. [ABSTRACT FROM AUTHOR]

• Unique bandgap alignment enhances charge transfer at the hetero-interface. • Non-wettability surface promotes the crystallization of the perovskite films. • PSCs achieve a V oc of 1.16 V and the PCE of 20.98%. • The stability of the PSCs based on m-TiO 2 /a-WO x ETL has been improved. Recently, the rapid improvement in power conversion efficiency (PCE) of perovskite solar cells (PSCs) with surprising and efficient PSCs is considered to be the most promising alternative to the next generation photovoltaic. In PSCs, the interfacial charge transfers between perovskite and electron transporting layers (ETLs) play an important role in enhancing the PCE , hysteresis, and stability. Here, an amorphous WO x (a-WO x) interlayer is interposed between the perovskite layer and mesoporous TiO 2 (m-TiO 2) layer to boost the hetero-interface charge transport. The room-temperature processed a-WO x has a wide bandgap and high electron mobility, which is capable of efficiently transporting photo-generated electrons, thereby reducing interfacial charge accumulation in the PSCs. Besides, we first found that the m-TiO 2 /a-WO x hybrid ETLs have better non-wettability, which subsequently improves the crystallization of the perovskite films by promoting the grain boundary mobility. Consequently, under optimized MAPbI 3 solar cells having m-TiO 2 /a-WO x hybrid ETLs exhibits the highest V oc of 1.16 V and the PCE of 20.98%. Stability tests indicate that the PCE value based on the m-TiO 2 /a-WO x device remains more than 91% after exposure to 45% humidity for 30 days in the dark at room temperature, much higher than the m-TiO 2 based cell, which retains about 70% of the initial PCE value. [ABSTRACT FROM AUTHOR]

The introduction of NCs and PFOAI can reduce the interface defects, enhanced its ultraviolet light utilization, and significantly improved the V OC and PCE of the device. [Display omitted] • Cs 3 MnBr 5 : Ce3+ nanocrystals and PFOAI are introduced into perovskite solar cells. • The synergistic passivation effect improves the Voc to 1.233 V. • The synergistic passivation effect of NCs and PFOAI improves the PCE to 24.24 %. • Non-encapsulated modified PSCs exhibit excellent long time, light and humidity stability. Interface engineering take as a crucial role in enhancing the performance of perovskite solar cells (PSCs). Here, we propose a comprehensive strategy to improve the performance and stability of PSCs through dual-interface modification approach. This strategy involves simultaneously introducing lead-free Cs 3 MnBr 5 : Ce3+ nanocrystals (NCs) between SnO 2 electron transport layer and the perovskite layer, as well as 1H,1H-Perfluorooctylamine iodide (PFOAI) at the interface between perovskite and Spiro-OMeTAD hole transport layer. Firstly, we successfully prepare Cs 3 MnBr 5 : Ce3+ NCs, which exhibits an extensive ultraviolet response and effective blue photoluminescence. The photoluminescence quantum yield of Cs 3 MnBr 5 : Ce3+ NCs can reach 90 %, demonstrating efficient photon down-conversion ability and efficient defect passivation. Simultaneously, the organic halide salt PFOAI with super-hydrophobic properties efficiently passivates defects on the surface of perovskite and improves moisture-resistance of perovskite films. Taking advantage of these synergistic effects, we achieve efficient PSCs based the Cs 0.05 (FA 0.83 MA 0.17) 0.95 Pb(I 0.83 Br 0.17) 3 and Cs 0.05 (FA 0.95 MA 0.05) 0.95 Pb(I 0.95 Br 0.05) 3 with power conversion efficiency (PCE) of 23.88 % and 24.24 %. We also achieved an ultrahigh open-circuit voltage (V OC) of 1.233 V, which represents one of the highest V OC values in a perovskite film with a bandgap of ∼1.60 eV. Additionally, the non-encapsulated double-interface modified PSCs exhibit long time, light and humidity stability. This study explores a novel and comprehensive strategy for manufacturing PSCs with high V OC , high PCE, and good stability. [ABSTRACT FROM AUTHOR]

[Display omitted] • Down-converter enhances device UV stability and UV light utilization. • CIGSe quantum dots broaden photoresponse range of perovskite solar cells to 920 nm. • CIGSe and down converters coordinated to enhance the light harvesting capacity. The light loss caused by the incomplete utilization of the solar energy spectrum is a key factor that impedes the photoelectric conversion efficiency of perovskite solar cells (PSCs). Hence, reducing the light escape through enhancing the utilization of ultraviolet (UV) light, and expanding the response of PSCs in the near-infrared (NIR) range is the key factor to further improve the photoelectric conversion efficiency (PCE) of PSCs. However, there is a lack of literature on engineering UV and NIR light harvesting at the same time. Herein, the NaYF 4 :Ce,Tb@NaYF 4 core–shell nanocrystals with efficient photon downconversion ability from UV to visible are designed to be embedded in the electron transporting layer (ETL), which serves as the photon downconverters and defect passivators, successfully improving the light response in both UV and visible region. The CIGSe quantum dots (QDs) with excellent infrared light harvesting ability, together with the plasmonic Au nanorods (NRs), are assembled in the hole transporting layer (HTL) to expand and improve the NIR light harvesting. The light response of the PSCs was successfully broadened to the NIR region from 800 to 920 nm. As a result, the champion PSC device insulating with NaYF 4 :Ce,Tb@NaYF 4 nanocrystals and CIGSe QDs demonstrates a remarkably increased PCE from 19.38% to 22.60%. The modified PSC devices also demonstrate highly improved UV and long-term stability. This work suggests a universal strategy to improve the UV and near-infrared light harvesting of PSCs, which is of great importance for fabricating PSCs with response to full spectrum. [ABSTRACT FROM AUTHOR]

• Single-walled carbon nanotubes acts as a double hole transport layer. • Multifunctional bulk organic heterojunction provides additional light harvesting. • Heterojunction and buffer layer enhance the stability of perovskite solar cells. Currently, the high-efficiency lead organic–inorganic hybrid perovskite solar cells (PSCs) can only utilize a relatively small fraction of sunlight (300–800 nm) due to the limited tunability of optical bandgap, which is the key factor limiting the further improvement of the photoelectric conversion efficiency (PCE) of PSCs. Here, we report a method to blend the narrow band gap non-fullerene acceptor molecule Y18 and the wide band gap donor molecule PM6 to form a multifunctional bulk organic heterojunction active layer. To avoid the loss of voltage and fill factor caused by the compromised hole transport layer (HTL), we introduce the single-walled carbon nanotubes as a buffer layer to fabricate a double HTL. The champion device displays a PCE improvement from 20.05% to 22.82% with a relative increase of 13.81%. After a deep examination of the mechanism, organic heterojunction provides the multifunctional roles as follows: (1) providing additional harvesting to the near-infrared light ranging of 800–950 nm; (2) passivating the perovskite surface and grain boundary to reduce the defect density; (3) promoting hole extraction from perovskite to HTLs by forming cascade energy levels. Moreover, the stability of PSCs is considerably enhanced because the introduction of organic heterojunction and buffer layer design isolated the natural degradation, which enhances the tolerance towards water and oxygen. Finally, a module group is fabricated by connecting two series modules in parallel, which is served as a power source to light the diode screen. This work demonstrates a buffer layer design for fabricating organic heterojunction-perovskite integrated solar cells to expand the near-infrared response, which provides a novel approach for designing integrated solar cells in the future. [ABSTRACT FROM AUTHOR]