Search

Phosphorescent materials have received considerable attention in organic solar cells (OSCs) due to their long emission lifetime and inhibited geminate recombination. Motivated by its particular photophysical property, herein, the spatially addressable bis(2‐benzo[b]thiophen‐2‐ylpyridine)(acetylacetonate)iridium(III) (Ir(bt)2(acac))/polystyrene‐b‐poly(4‐vinylpyridine) (PS‐b‐P4VP) as a photoactive floating‐gate is first demonstrated to explore the application of phosphorescent material on the photo‐responsive characteristics of photomemory and artificial photonic synapse. By manipulating the interfacial area between Ir(bt)2(acac)/PS‐b‐P4VP and active channel by a solvent annealing process, an ON/OFF current ratio of 103 and a low programming time of 700 ms can be achieved. The current study addresses the exciton lifetime of photoactive material functions in photomemory and highlights the interfacial area between photoactive materials and charge‐carrier transporting materials in reducing photo‐programming time. [ABSTRACT FROM AUTHOR]

With the power conversion efficiencies of perovskite solar cells (PSCs) exceeding 25%, the PSCs are a step closer to initial industrialization. Prior to transferring from laboratory fabrication to industrial manufacturing, issues such as scalability, material cost, and production line compatibility that significantly impact the manufacturing remain to be addressed. Here, breakthroughs on all these fronts are reported. Carbon‐based PSCs with architecture fluorine doped tin oxide (FTO)/electron transport layer/perovskite/carbon, that eliminate the need for the hole transport layer and noble metal electrode, provide ultralow‐cost configuration. This PSC architecture is manufactured using a scalable and industrially compatible electrospray (ES) technique, which enables continuous printing of all the cell layers. The ES deposited electron transport layer and perovskite layer exhibit properties comparable to that of the laboratory‐scale spin coating method. The ES deposited carbon electrode layer exhibits superior conductivity and interfacial microstructure in comparison to films synthesized using the conventional doctor blading technique. As a result, the fully ES printed carbon‐based PSCs show a record 14.41% power conversion efficiency, rivaling the state‐of‐the‐art hole transporter‐free PSCs. These results will immediately have an impact on the scalable production of PSCs. [ABSTRACT FROM AUTHOR]

Multijunction/tandem solar cells have naturally attracted great attention because they are not subject to the Shockley–Queisser limit. Perovskite solar cells are ideal candidates for the top cell in multijunction/tandem devices due to the high power conversion efficiency (PCE) and relatively low voltage loss. Herein, sandwiched gold nanomesh between MoO3 layers is designed as a transparent electrode. The large surface tension of MoO3 effectively improves wettability for gold, resulting in Frank–van der Merwe growth to produce an ultrathin gold nanomesh layer, which guarantees not only excellent conductivity but also great optical transparency, which is particularly important for a multijunction/tandem solar cell. The top MoO3 layer reduces the reflection at the gold layer to further increase light transmission. As a result, the semitransparent perovskite cell shows an 18.3% efficiency, the highest reported for this type of device. When the semitransparent perovskite device is mechanically stacked with a heterojunction silicon solar cell of 23.3% PCE, it yields a combined efficiency of 27.0%, higher than those of both the sub‐cells. This breakthrough in elevating the efficiency of semitransparent and multijunction/tandem devices can help to break the Shockley–Queisser limit. [ABSTRACT FROM AUTHOR]

In article number 1804419, Congcong Wu, Shashank Priya, and co‐workers develope a dual‐functional PMMA‐fullerene complex, where the fullerene C60 dwells in the caves of the PMMA polymer chain. The PMMA‐fullerene complex is incorporated into the perovskite layer, which resides along the grain boundary of the perovskites. The fullerene reduces the charge carrier recombination and the PMMA polymer improves the stability of the perovskite solar cell. [ABSTRACT FROM AUTHOR]

Lead halide perovskite solar cells (PSCs) have demonstrated great potential for realizing low‐cost and easily fabricated photovoltaics. At this juncture, power conversion efficiency and long‐term stability are two important factors limiting their transition. PSCs exhibit rapid environmental degradation since the perovskite layer is very sensitive to factors such as humidity, temperature, and ultraviolet light. Here, a novel successful approach is demonstrated that simultaneously improves the efficiency and stability of PSCs. This approach relies on incorporation of a dual‐functional polymethyl methacrylate (PMMA)–fullerene complex into the perovskite layer. The fullerene within perovskite layer forms a localized dipole‐like electric field that favors electron–hole separation, resulting in significant improvement in current density and fill factor with conversion efficiency reaching 18.4%. The molecular‐scale coating of hydrophobic PMMA on the perovskite grain boundary effectively blocks moisture penetration into the perovskite, thereby, significantly improving the stability against moisture, heat, and light. The PSCs with PMMA–fullerene complex showed no photovoltaic performance degradation for 250 d and exhibited 60 times higher stability compared to the state‐of‐the‐art devices under continuous 1 sun illumination in ambient air. Polymethyl methacrylate is coated on a perovskite grain boundary, blocking moisture penetration. The distributed C60 clusters create a dipole‐like electric field inside the perovskite layer, which favors exciton dissociation, and improves the conversion efficiency of perovskite solar cells. [ABSTRACT FROM AUTHOR]