Propeller-Shaped, Triarylamine-Rich, and Dopant-Free Hole-Transporting Materials for Efficient n–i–p Perovskite Solar Cells

Abstract

By introducing six triarylamine groups to a hexaphenylbenzene (HPB) or a hexakis­(2-thienyl)­benzene (HTB) core, two propeller-shaped, triarylamine-rich, and low-cost hole-transporting materials (HTMs), which are termed as HPB-OMe and HTB-OMe, respectively, with considerable hole mobility, were obtained by easy synthetic routes. Solid-state planar perovskite CH3NH3PbI3 solar cells (PSCs) with two new HTMs showed high power conversion efficiencies (12.9% for HPB-OMe and 17.3% for HTB-OMe in forward scans) under standard 100 mW cm–2 AM 1.5G illumination without doping. A comparison of matched-degree of energy levels, hole-transporting ability, photovoltaic conversion efficiencies, and recombination of the two HTMs indicated that developing multi-triarylamine- and thiophene-rich molecules provides candidate and efficient dopant-free HTMs for PSCs.

Development of Dopant‐Free Organic Hole Transporting Materials for Perovskite Solar Cells

“…Meanwhile, hysteresis free small scaled devices based on XY1 showed a competitive PCE of 18.78%. Further, several novel chemical structures of dopant‐free HTMs with moderate device data have been reported (summarized in Table 1 and 2) yet not discussed in detail here …”

Hexaarylbenzene based high-performance p-channel molecules for electronic applications

“…Cui et al 148 developed the non-fullerene triphenylamine tailored HAB derivatives for perovskite photovoltaic applications. Propeller-shaped hexaphenyl (80) and hexathienyl (81) benzene derivatives have been designed with triarylamine moiety, due to the good hole-transporting property (Fig.…”

A Review on Solution‐Processable Dopant‐Free Small Molecules as Hole‐Transporting Materials for Efficient Perovskite Solar Cells

“…SM-HTMs with simple rings as the core units contain numerous molecules, but the efficiency of them can hardly reach 19% [105][106][107][108][109][110][111][112][113][114][115][116][117][118]120,159] until the recent report with a PCE of 21.0%. [119] Here we divided them into three classes, those with only TPA/DPA and benzene/thiophene units, [105][106][107][108][109][110][113][114][115][116][117]119] those with other donor units, [111,118,120] and those with acceptor units (Figure 6). [112,159] The representative one of the first class was introduced by Chen et al [113] where the molecule HTB-OMe was composed by a benzene core, six thiophene spacer, and six TPA arms.…”

“…[119] Here we divided them into three classes, those with only TPA/DPA and benzene/thiophene units, [105][106][107][108][109][110][113][114][115][116][117]119] those with other donor units, [111,118,120] and those with acceptor units (Figure 6). [112,159] The representative one of the first class was introduced by Chen et al [113] where the molecule HTB-OMe was composed by a benzene core, six thiophene spacer, and six TPA arms. Due to the rich thiophene units that could offer better electroconductivity than benzene unit, the HTM gained a higher hole mobility of 5.482 × 10 −4 cm 2 V −1 s −1 compared with the value of 1.025 × 10 −4 cm 2 V −1 s −1 for the analogue with benzene spacers.…”