High-efficiency (over 33 %) indoor organic photovoltaics with band-aligned and defect-suppressed interlayers

Abstract

In recent years, the emergence of the Internet of Things (IoT) has led to growing interest in the use of organic-based artificial light cells (OALCs; indoor organic photovoltaics) to harvest ambient light energy. This study employs atomic layer deposition (ALD)-processed vanadium oxide (V2O5) hole-transport-layers (HTLs) in non-fullerene acceptor-based OALCs to achieve record power conversion efficiency (PCE) exceeding 33 % under a light-emitting diode lamp (19500 lx; light intensity IL = 4.5 mW/cm2). The material most widely used for HTLs is poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). OALCs with ALD-processed V2O5 HTLs substantially outperform those with PEDOT:PSS HTLs because they have superior hole selectivity, excellent electron-blocking, a smaller interfacial area, and substantially enhanced step coverage which significantly suppresses charge recombination. Moreover, the proposed V2O5-based OALCs have diffusion-free characteristics into the photoactive region and demonstrate excellent performance stability, maintaining a PCE of 92 % after 1000 h under ambient conditions. The results provide insights that enable simultaneous improvements in the efficiency and ambient stability of OALCs for low-powered IoT applications.