Photoactivated p-Doping of Organic Interlayer Enables Efficient Perovskite/Silicon Tandem Solar Cells

Abstract

Solution-processed organic semiconductor layers on rough surfaces tend to vary widely in thickness, significantly hindering charge extraction in relevant optoelectronic devices. Herein, we report the photoactivated p-doping of hole-transporting material (HTM) to enhance hole extraction for (textured) perovskite/silicon tandem solar cells, making the device performance less sensitive to the variation of hole transport layer thickness. We used the ionic compound 4isopropyl-4′-methyldiphenyliodonium tetrakis(penta-fluorophenyl-borate) (DPI-TPFB) as a p-type dopant in poly(triaryl amine) (PTAA), which we used as the HTM. We observed that light soaking DPI-TPFB-doped PTAA shows approximately 22 times higher conductivity compared with an undoped PTAA film, which translated into an improved fill factor (FF) for tandem solar cells. Our tandem solar cells achieved an ∼80% FF and 27.8% efficiency and operated at their maximum power point for 200 h without loss of performance, in addition to retaining ∼83% of initial performance over a month of operation in an outdoor environment.

Alkyl fluorene-based cross-linkable hole transport materials with high triplet energy for high-efficiency solution-processed green PHOLEDs

“…The elevated hole mobility is due to the oxidation of the triphenylamine moiety by hydrogen tetrakis(pentafluorophenyl)borate, thus generating cationic radicals. 15,35,36 The mechanism for the generation of hydrogen tetrakis(pentafluorophenyl)borate is described in Fig. S22 (ESI†).…”

Recent Advances in Wide-Bandgap Organic–Inorganic Halide Perovskite Solar Cells and Tandem Application

“…Some researchers would like to improve the conductivity of PTAA by doping with small molecules like F4-TCNQ. Zheng et al reported the p-doping of PTAA to facilitate hole extraction for 2-T perovskite/ silicon TSCs, making the device performance less sensitive to the thickness of PTAA [177]. The p-doping with ionic compound 4-isopropyl-4'-methyldiphenyliodonium tetrakis(penta-fluorophenyl-borate) (DPI-TPFB) dopant is activated by light-soaking treatment, resulting in nearly 22 times higher conductivity than that of pristine PTAA.…”

Pivotal Routes for Maximizing Semitransparent Perovskite Solar Cell Performance: Photon Propagation Management and Carrier Kinetics Regulation

“…As the most promising method to approach the S-Q limit efficiency of perovskites, TSCs will also make great contribution to promoting the commercial application of ST-PSCs. [172,173]…”