A hot carrier perovskite solar cell with efficiency exceeding 27% enabled by ultrafast hot hole transfer with phthalocyanine derivatives

Abstract

Hot carrier solar cells could achieve efficiencies exceeding the Shockley–Queisser limit by collecting hot carriers before they cool down. With the hot-phonon bottleneck effect, hot carrier collection may be favorable at high carrier densities in concentrator photovoltaics. In this work, utilizing the excellent thermal stability of a phthalocyanine (Pc) hole transport layer (HTL), we constructed a hot hole collecting HTL. A methylthiotriphenylamine-based SMePc achieved an extraction velocity of 78 900 cm s⁻¹, corresponding to a collecting distance of ∼79 nm. With this HTL, an efficiency of 24.95% and certified efficiency of 24.43% are achieved under 1 sun illumination with over 3000 h operational stability in N₂ (60 °C) and over 1000 h at 85 °C. With a solar concentrator, an increase in open-circuit voltage (V_OC) above the theoretical cold carrier line is observed, and a record efficiency of 27.30% is achieved under 5.9 sun illumination for a single-junction perovskite solar cell. Our strategy demonstrated the potential application of high-efficiency hot carrier solar cells.