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A bandgap gradient at the front surface of solar absorbers can effectively suppress surface recombination while not affecting photocurrent. Herein, it is demonstrated that a front‐surface gradient can be formed in an inverted perovskite cell by introducing perovskite quantum dots (QDs) between the hole‐transporting layer (HTL) and the remaining absorber. Ultraviolet photoelectron spectroscopy reveals that, with the addition of CsPbBr3 QDs onto the HTL substrate, the subsequently deposited MAPbI3 is converted from mild p‐type to n‐type, and the resultant band alignment can effectively reduce the electron concentration at the front surface without significantly affecting hole extraction. Multiple independent characterizations further confirm the reduction of surface recombination. As a result, the inverted MAPbI3 cells exhibit an open‐circuit voltage of 1.154 V, which translates to a nonradiative recombination loss of 0.15 V and a power conversion efficiency of 20.51%. [ABSTRACT FROM AUTHOR]

The recombination flux in a solar cell is determined by not only recombination centers, but also the spatial distribution of minority carriers. For halide perovskite solar cells (PSCs), although there has been a tremendous amount of work focusing on defect passivation, the issue of carrier distribution is not as well studied as for other types of solar cells. Here in this work, with the incorporation of perovskite quantum dots, the concept of the front surface gradient in PSCs using a solution process is successfully realized. Evidenced by multiple characterization techniques, the minority carriers are pushed away from the defect‐rich surface by the gradient of valence band maximum, which effectively reduces surface recombination without compromising photocurrent. As a result, the normal structured hybrid PSCs and MAPbI3 cells exhibit open‐circuit voltages exceeding 93% and 90% of their respective Shockley–Queisser limits, and the power conversion efficiencies reach 22.36% and 20.53%, respectively. [ABSTRACT FROM AUTHOR]