Interface Optimization via Fullerene Blends Enables Open‐Circuit Voltages of 1.35 V in CH₃NH₃Pb(I_0.8Br_0.2)₃ Solar Cells

Abstract

Nonradiative recombination processes are the biggest hindrance to approaching the radiative limit of the open‐circuit voltage for wide bandgap perovskite solar cells. In addition to high bulk quality, good interfaces and good energy level alignment for majority carriers at charge transport layer‐absorber interfaces are crucial to minimize nonradiative recombination pathways. By tuning the lowest‐unoccupied molecular‐orbital of electron transport layers via the use of different fullerenes and fullerene blends, open‐circuit voltages exceeding 1.35 V in CH3NH3Pb(I0.8Br0.2)3 device are demonstrated. Further optimization of mobility in binary fullerenes electron transport layers can boost the power conversion efficiency as high as 18.9%. It is noted in particular that the Voc fill factor product is >1.096 V, which is the highest value reported for halide perovskites with this bandgap.

Tailoring the Energy Manifold of Quasi‐Two‐Dimensional Perovskites for Efficient Carrier Extraction

“…[54] This involves tuning carrier extraction layers with favorable energy levels [55] and optimizing the charge transport properties. [56,57] Specifically, since BCP does not extract carriers from high-n phases, one possible strategy to simultaneously extract carriers from low-n and highn phases is by blending BCP with commonly employed 3D band-edge carrier extractors [58] such as PCBM. This could be the focus of a future work.…”

Two birds with one stone: dual grain-boundary and interface passivation enables >22% efficient inverted methylammonium-free perovskite solar cells

“…the FF losses due to series/shunt resistance, non-ideal n id and non-radiative recombination. 34,125 As shown in Fig. S18, the ideal device exhibits a PCE of 27.8% with a FF of 90.3% for both Ref and GBP&SP.…”

Two Birds with One Stone: Dual Grain-Boundary and Interface Passivation Enables > 22% Efficient Inverted Methylammonium-Free Perovskite Solar Cells

“…the FF losses due to series/shunt resistance, non-ideal n id and non-radiative recombination. 34,125 As shown in Fig. S18 (ESI †), the ideal device exhibits a PCE of 27.8% with a FF of 90.3% for both Ref and GBP&SP.…”