Search

Perovskite single crystals (SCs) have gained significant interest in various applications owing to their superior optoelectrical and physical characteristics as compared to polycrystalline films. However, a considerable portion of incident light is typically reflected at the surface of perovskite SCs, leading to insufficient light absorption within the crystal bulk, ultimately resulting in reduced performance of SC‐based photodetectors. In the present work, an inverted pyramid‐shaped structure is in situ introduced on the surface of an MAPbBr3 SC during the crystal growth process, which can reduce light reflection in the surface region and enhance light absorption of the SC. Additionally, the hydrophobic small molecule copper (II) phthalocyanine (CuPc) is thermally evaporated onto the SC, forming a CuPc/MAPbBr3 heterojunction for the first time. The CuPc/pyramid‐shaped MAPbBr3 heterojunction‐based photodetector exhibits self‐powered characteristics and superior optoelectrical performance, achieving a photocurrent of greater than 10−5 A (10−7 A), a responsiveness of 257 mA W−1 (8.84 mA W−1), and a detection rate of 2.98 × 1012 Jones (1.02 × 1011 Jones) at −2 V (0 V) bias. Simultaneously, the device demonstrates excellent long‐term stability under high humidity conditions, retaining 90.5% of its initial photocurrent even after 60 days in a 60–80% humidity environment. [ABSTRACT FROM AUTHOR]

Compared with polycrystalline films, perovskite single crystal is considered as a promising photoelectric material due to its unique advantages in quantum efficiency and carrier diffusion length. In this work, the micron-thickness MAPbBr3 single crystal was prepared through a highly repeatable process based on the crystal seed dissolution-growth method. A heterojunction of MAPbBr3/WO3 single crystal was realized through a simple thermal evaporation process, and the integrated C/MAPbBr3/WO3/C device demonstrated self-powered characteristics and high photoelectric performance, which showed good responsivity of about 111 mA/W, detectivity of 9.64×1011 Jones and fast response speed (0.11/0.56 ms). Meanwhile, the device exhibited good rectification performance (ratio of 125 at ±2 V) and reduced dark current due to the built-in electric field formed in the heterojunction. This study provides a facile, flexible, and highly repeatable method for the preparation of high-performance photodetectors based on MAPbBr3 single crystals with micrometer thickness. [ABSTRACT FROM AUTHOR]

Heterojunctions were widely studied as semiconductor structures for photoelectronic devices such as solar cells and photodetectors, due to their ability for dark current reduction and self-powered operation. In this work, an α-FAPbI3/MAPbI3 single crystal concentric annular lateral heterojunction was successfully fabricated by liquid phase epitaxy under ambient conditions. Compared to a vertical heterojunction structure, a lateral structure can reduce the incident light loss and interfacial accumulation of defects. In addition, the selection of the same halogen sites can resolve the issue of phase separation stemming from different halogen ions in the perovskite materials. By fabricating an α-FAPbI3/MAPbI3 single crystal concentric annular lateral heterojunction, a wide spectrum response from ultraviolet to near-infrared is attained. Furthermore, depending on the reduction of the potential barrier due to the pyro-phototronic effect generated by the MAPbI3 single crystals and the presence of the built-in electric field, the α-FAPbI3/MAPbI3 single crystal lateral heterojunction-based photodetector exhibits a high responsivity of 27.50 mA W−1, a specific detectivity of 7.71 × 1011 Jones, a fast response speed of 62.7 μs and self-powering ability. These results suggest that lateral perovskite single crystal heterojunctions with the same halogen are promising configurations for photodetectors and other optoelectronic devices and systems. [ABSTRACT FROM AUTHOR]

All-inorganic Bi-based perovskites have attracted much attention due to their excellent stability, environmentally friendly, and low-cost solution processability. However, due to the large exciton binding energy and small light absorption coefficient, the performance of the Bi-based perovskite photodetector (PD) is far behind of the traditional Pb-based perovskite PDs. In this work, the lead-free all-inorganic Cs3Bi2I9 (CBI) perovskite single crystal was synthesized by a space-confined antisolvent-assisted crystallization method for high-performance, semi-transparent, and self-driven PDs with an ITO/SnO2/CBI/PTAA/Au/ITO structure. Electrical and optical properties of Au/ITO transparent electrode were studied considering its figure of merit and device quantum efficiency through optimizing the Au thickness. Finally, our optimized semi-transparent device showed excellent self-driven performance with a large on/off ratio of ∼5700, a high responsivity of 52.06 mA/W, a high detectivity of >1012 Jones, and a large linear dynamic range of up to 140.7 dB. In addition, our device demonstrated excellent characteristics to the weak light detection and the long-term stability. The Au/ITO electrode was adopted and tailored to balance the device performance and transparency, which provides a good route for developing high-performance and transparent devices in the future. [ABSTRACT FROM AUTHOR]

P‐type semiconductor cuprous oxide (Cu2O) offers promising optoelectronic applications such as solar cells and photodetectors owing to its considerable absorption coefficients and high carrier mobility. However, polycrystalline Cu2O films with low carrier mobility resulting from excessive grain boundaries and structure disorder fail to meet the demands for these optoelectronic applications. Here a stress‐assisted thermal oxidation method to fabricate p‐type <110>‐textured quasi‐single crystalline Cu2O (c‐Cu2O) wafers with centimeter‐scale grains is developed. It is found that strain energy induced by thermal contact stress plays a critical role in crystal growth. The resultant <110>‐textured quasi‐single c‐Cu2O wafers exhibit excellent crystallinity with rocking curve having a low full width at half maximum of 0.022°, a low defect density of 2 × 1011 cm−3, a high mobility exceeding 100 cm2 V−1 s−1, and a long minority lifetime of 98.5 µs. Such quasi‐single c‐Cu2O wafers lead to efficient solar cells with an open‐circuit voltage of 0.95 V and highly responsive photodetectors with superior cycling stability. These results indicate not only the advancement of fabricating high‐quality Cu2O wafers upon controllable methodology but also the promising optoelectronic applications using p‐type metal oxide semiconductors. [ABSTRACT FROM AUTHOR]

Nickel oxide (NiOx) as a hole-transporting layer (HTL) in perovskite solar cells (PSCs) has been studied extensively in recent years. However, unlike the solution-processed NiOx films, magnetron sputtered NiOx exhibits relatively low conductivity and imperfect band alignment with perovskites, severely limiting the device performance of PSCs. In this study, a synergistically combined strategy consisting of triple interface treatments – including post-annealing, O2-plasma, and potassium chloride treatments – is employed to modulate the optoelectronic properties of the sputtered NiOx films. Through this approach, we successfully obtained NiOx films with increased carrier density and conductivity, better energy level alignment with the perovskite absorber layer, reduced interface trap density, and improved interfacial charge extraction. PSCs using this modified sputtered NiOx as the HTL deliver a highest stabilized efficiency of 18.7%. Our result offers an alternative method to manipulate sputtered NiOx thin film properties and thereby sheds light on a manufacturing pathway to perovskite solar cells featuring sputtered NiOx HTL. [ABSTRACT FROM AUTHOR]

The electron transport layer (ETL) is a critical component in planar single junction or tandem perovskite solar cells (PSCs), dominating the separation and electron extraction of charge carriers. Herein, we introduce a facile route to synthesize a SnO2 quantum dot (QD) colloidal solution at room temperature using an alcohol-based solvent with the additive of deionized-water. A superior homogeneous ETL is obtained by spin coating of the QD colloidal solution with post-deposition annealing. Compared to the ETL prepared with the SnCl2·2H2O anhydrous alcohol solution, the champion power conversion efficiency of PSCs deposited on the SnO2 QD based ETL is raised to 20.1% from 16.5%. The better performance is attributed to the excellent optical and electronic properties of the SnO2 QD based ETL. Experimental analyses reveal that the SnO2 QD based ETL enhances electron extraction and suppresses charge recombination, leading to improvement of solar cell performance. The appropriate concentration of the SnO2 QD based solution is explored and the appropriate ratio of anhydrous alcohol to deionized water of the SnO2 colloidal solution is obtained. Our results show the great potential of low temperature synthesized SnO2 QD films for application as ETLs or interconnecting buffer layers for future highly efficient and reproducible low-temperature processed tandem PSCs. [ABSTRACT FROM AUTHOR]

Self-powered light-emitting photodetectors (SLEPs) can simultaneously transmit and receive information using light, offering huge potential for applications in interactive communication systems. However, high-performance SLEPs are very hard to achieve due to the seriously contradictory principles of carrier transport in SLEPs. In this study, a novel structure based on a ZnO hollow ball/CsPbBr3 heterojunction, in which ZnO hollow balls function as an ultraviolet (UV) response center and CsPbBr3 is designed to be a green light-emitting material, is reported as a high-performance SLEP. Since the ZnO hollow balls have superior light trapping characteristics for UV light, the device shows a huge UV response with the on/off ratio and detectivity up to 16 527 and 2.4 × 1013 Jones, respectively. Moreover, it displays blue emission with a low threshold voltage because of CsPbBr3. Compared with the traditional ZnO/GaN structure devices, the device showed enhanced dual-functional performance at various wavelengths due to the insertion of CsPbBr3, which resulted in a better contact interface and green-light emission center. Our structure separating the light-responsive and emitting active regions avoids the contradictory principles of carrier transport, which may provide new access to gain high-performance dual-functional devices. [ABSTRACT FROM AUTHOR]