Curing the vulnerable heterointerface via organic-inorganic hybrid hole transporting bilayers for efficient inverted perovskite solar cells

To promote the practices of perovskite photovoltaics,it requires to develop efficient perovskite solar cells(PVSCs)standing long-time operation under the adverse environments.Herein,we demonstrate that the tailor-made conjugated polymers as conductive adhesives stabilized the originally redox-reactive heterointerface between perovskite and metal oxide,facilitating the access of efficient and stable inverted PVSCs.It was revealed that bithiophene and phenyl alternating conjugated polymers with partial glycol chains atop of the metal oxide layer has resulted in effective organic-inorganic hybrid hole transporting bilayers,which allow maintaining efficient hole extraction and transport,meanwhile preventing halide migration to directly contact with the nickel oxide(NiO_(x))layer.As a result,the corresponding inverted PVSCs with the organic-inorganic hole transporting bilayers have achieved an excellent power conversion efficiency of 23.22%,outperforming 20.65% of bare NiO_(x)-based devices.Moreover,the encapsulated PVSCs with organic-inorganic bilayers exhibited the excellent photostability with 91% of the initial efficiency after 1000-h one-sun equivalent illumination in ambient conditions.Overall,this work provides new insights into stabilizing the vulnerable heterointerface for perovskite solar cells.

A multifunctional and scalable fullerene electron transporting material for efficient inverted perovskite solar cells and modules

The interfacial properties between charge transporting material and perovskite(PVSK)play critical roles in governing the photovoltaic performances of perovskite solar cells(PVSCs).Herein,we develop a multifunctional fulleropyrrolidine(FMG)as an electron transporting material(ETM),which facilitates the construction of efficient and stable inverted PVSCs and modules.It revealed that the facile and scalable FMG possesses not only excellent electron extraction capabilities,but also multi-groups to simultaneously passivate PVSKs via Lewis acid-base and hydrogen bonding interactions.The coating of FMG onto PVSK interestingly yields a dense and interactive layer with the graded ETM-PVSK heterojunction architecture.As a result,FMGbased PVSCs demonstrate a champion efficiency of 23.8%,outperforming 21.0%of PCBM-based devices.FMG could also be utilized to improve photovoltaic performance of large-scale modules.In addition,FMG has successfully elongated the lifetime of the corresponding PVSCs,maintaining 85%of the initial performance after the continuous 60-day one sun equivalent illumination in ambient.

Manipulating the film morphology evolution toward green solvent-processed perovskite solar cells

High-performance perovskite solar cells(PVSCs)with low energy consumption and green processing are highly desired,but constrained by the difficulty in morphology control and the poor understanding on morphology evolution mechanisms.To address this issue,here we studied the effect of antisolvents on the perovskite film formation.We found that both the antisolvents and the perovskite composition affect the perovskite film morphology greatly via influencing the intermediate phase,and different perovskite compositions require different antisolvents to reach the optimal morphology.This provides the opportunity to achieve high-performance PVSCs with green antisolvent,that is,isopropanol(iPA)by changing the perovskite compositions,and leads to a powerconversionefficiency(PCE)of 21.50% for PVSCs based on MA_(0.6)FA_(0.4)PbI_(3).Further,we fabricated“fully green”PVSCs with all layers prepared by green sol-vents,and the optimal PCE can reach 19%,which represents the highest among PVSCs with full-green processing.This work provides insight into the perovskite morphology evolution and paves the way toward“green”processing PVSCs.