Enhancing Inverted Perovskite Solar Cell Efficiency with Vanadium Oxide-Modified PEDOT:PSS Hole Transport Layer

Poly(3,4-ethylenedioxythiophene): polystyrenesulfonate (PEDOT:PSS) is widely used as a hole transport layer (HTL) in emerging solar cells. It is highly compatible with roll-to-roll deposition, paving the way for utilization in flexible solar cells. However, its mismatched energy levels and acidity limit its performance and stability. This study focuses on the modification of PEDOT:PSS HTL with vanadium oxide $\left(V_{2} O_{5}\right)$ additive to improve the performance of inverted $p-i-n$ perovskite solar cells (PSCs). The $V_{2} O_{5}$ was prepared from an aqueous ammonia solution and directly added to the PEDOT:PSS solution. Devices employing $V_{2} O_{5}$:PEDOT:PSS (VPP) HTL with a concentration of $8 mg/ml(w/v)$ exhibit remarkable performance improvement compared to devices using pristine PEDOT:PSS, with the power conversion efficiency (PCE) rising from 7.7 % to 9.0 %. Furthermore, key parameters, including open-circuit voltage ($V_{o c}$), short-circuit current ($J_{S C}$), and fill factor (FF), all showed improvements, recorded at 0.95 V, 16.0 $mAcm^{-2}$, and 58.6 %, respectively. Additionally, the responsiveness of light-to-current conversion exhibits a notable increase, highlighting the potential $V_{2}O_{5}$ additive, prepared using a simple method, to achieve superior performance in inverted p $i-n$ PSC. The finding also opens avenues for further exploration of other metal oxide additives, addressing specific challenges in HTL deposition.