Recent Progress of Layered Perovskite Solar Cells Incorporating Aromatic Spacers

Layered two dimensional(2D) or quasi-2D perovskites are emerging photovoltaic materials due to their superior environment and structure stability in comparison with their 3D counterparts. The typical 2D perovskites can be obtained by cutting 3D perovskites along < 100 > orientation by incorporation of bulky organic spacers, which play a key role in the performance of 2D perovskite solar cells(PSCs). Compared with aliphatic spacers, aromatic spacers with high dielectric constant have the potential to decrease the dielectric and quantum confinement effect of 2D perovskites, promote efficient charge transport and reduce the exciton binding energy, all of which are beneficial for the photovoltaic performance of 2D PSCs. In this review, we aim to provide useful guidelines for the design of aromatic spacers for 2D perovskites. We systematically reviewed the recent progress of aromatic spacers used in 2D PSCs. Finally, we propose the possible design strategies for aromatic spacers that may lead to more efficient and stable 2D PSCs.

Small molecule donors with different conjugated π linking bridges: Synthesis and photovoltaic properties

Three small molecule(SM)donors,namely B-T-CN,B-TT-CN and B-DTT-CN,with differentπconjugated bridges were synthesized in this research.Interestingly,with the conjugated fused rings of theπlinking bridge increasing,the SM HOMO levels exhibit a decline tendency with–5.27 eV for B-T-CN,–5.31 eV for B-TT-CN and–5.40 eV for B-DTT-CN.After blending the SM donors with the fullerene acceptor PC71BM,the all SM organic solar cells(OSCs)achieved high Vocs of 0.90 to 0.96 V.However,the phase separation morphology and molecule stacking are also unexpectedly changed together with the enhancement of conjugated degree ofπbridges,resulting in a lower power conversion efficiency(PCE)for the B-DTT-CN:PC71BM device.Our results demonstrate and provide a useful way to enhance OSC Voc and the morphology needs to be further optimized.

Recent Progress of Inorganic Hole-Transport Materials for Perovskite Solar Cells

Perovskite solar cells (PSCs) have achieved significant progress in the past decade and a certified power conversion efficiency (PCE) of 26.0% has been achieved.The widely used organic hole transport materials (HTMs) in PSCs are typically sensitive to the moisture environment and continuous light exposure.In contrast,the inorganic HTMs benefiting from their outstanding merits,such as excellent environmental stability,are considered as alternatives and have attracted much attention in PSCs.In this review,we provide a comprehensive summary of the fundamental properties and recent progress of inorganic HTMs in n-i-p and p-i-n structured PSCs.Additionally,we emphasize the importance of inorganic HTMs in the development of highly efficient and stable PSCs.

Surface in-situ reconstruction boosting the efficiency of inorganic perovskite solar cells

This article highlights recent advancements in inorganic perovskite solar cells(PSCs)published in Nature Energy by You et al.[1].They developed an innovative surface in-situ reconstruction(SISR)method for inorganic perovskites by directly spin-coating the fluoride salts in isopropanol(IPA)solution onto the inorganic perovskite film followed by thermal annealing.