Polarizable High‐Index Nanoparticles Used for Light‐Induced Crystal‐Silicon Passivation and Dielectric Antenna for High‐Efficiency Solar Cell

Abstract

Heterojunction crystal‐silicon (c‐Si) solar cells generate current from harvesting light via sweeping excited carriers away under built‐in asymmetry through amorphous silicon layers. However, loss of energy beyond the bandgap is known to hinder their efficiency. Herein, a strategy is provided to convert short‐wavelength energy into a polarization electrical field and the light dielectric antenna effect, where enhanced surface passivation and carrier collection occur simultaneously. By depositing an ultrathin polarizable nanoparticle layer on a transparent conducting oxide (TCO), a light‐induced electrical field is built up by light‐harvesting accumulation, which benefits for c‐Si surface passivation. An enchanting open‐circuit voltage (Voc) of 736.6 mV for the light‐induced field‐effect solar cell is achieved. In addition, the high‐index dielectric nanoparticles generate more photons to be absorbed in the long‐wavelength in c‐Si solar cells, which results in enhanced short‐circuit current (Jsc). As a result, benefiting from the light‐induced building‐up extra field and dielectric antenna effect, the device yields a power conversion efficiency of 22.41%, with the maximal improvement of Voc (≈4 mV), Jsc (≈0.4 mA cm−2), and fill factor (≈1%), respectively. This work provides a strategy to enhance solar cell efficiency by continuously harvesting beyond‐bandgap light to offer an additional asymmetrical field and the light antenna effect.