Hydrogen Tetrachloroaurate-Modulated PEDOT:PSS film assembled with conductive NPB buffer layer for High-Performance planar perovskite solar cells

Abstract

• Inorganic HAuCl 4 doping combined organic NPB post-treatment strategy was proposed. • High PCE of 19.20% for Au@PEDOT:PSS/NPB PSCs is achieved on rigid substrate. • Flexible Au@PEDOT:PSS/NPB PSCs achieve 14.04% PCE with strong wrinkle resistance. • Improved hysteresis and stability of PSCs are realized via synchronous regulation. The further improvements in optoelectronic properties, hydrophobicity of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hole transport layers, as well as regulation of defect states within devices are essential to promote the continued development of inverted p-i-n rigid and flexible planar perovskite solar cells (PSCs). However, the strong hygroscopicity, poor surface morphology, lower work function and coil configuration of pristine PEDOT:PSS films are detrimental to their own performance and growth dynamics process of perovskites, often resulting in sever energy losses and poor device performance. Herein, hydrogen tetrachloroaurate (III) hydrate (HAuCl 4 ·3H 2 O) additive is combined with a conductive N,N'-Bis-(1-naphthalenyl)-N,N'-bis-phenyl-(1,1′-biphenyl)-4,4′-diamine (NPB) buffer layer to boost device performance by systematically modulating PEDOT:PSS and perovskite film. Wherein, the redox reaction between PEDOT:PSS and HAuCl 4 can cause phase segregation of PEDOT:PSS, improving the hydrophobicity, electrical conductivity, work function and surface morphology of the films. The reduced gold nanoparticles will produce localized surface plasmon resonance effects, thus enhancing the utilization of solar radiation by perovskite films. Furthermore, the suitable energy level alignment of NPB layer relative to perovskite and Au@PEDOT:PSS films will sufficiently exploit the dissociative excitons to facilitate effective hole transport, and the N atoms in NPB can also passivate defects at the interface by binding to uncoordinated Pb 2+ ions, thereby reducing non-radiative open-circuit voltage loss and increasing short-circuit current density. A high power conversion efficiency (PCE) of 19.20% can be achieved for MA 0.85 FA 0.15 PbI 3 based p-i-n PSCs with negligible hysteresis and enhanced stability of devices. Similarly, the corresponding flexible device achieves a PCE of 14.04% with improved crumpling durability throughout low temperature preparation conditions below 140 °C. Our work presents a facile method to prepare high-efficient inverted PSCs while achieving improved long-term device stability.