Matching Charge Extraction Contact for Infrared PbS Colloidal Quantum Dot Solar Cells

Abstract

Infrared solar cells (IRSCs) can supplement silicon or perovskite SCs to broaden the utilization of the solar spectrum. As an ideal infrared photovoltaic material, PbS colloidal quantum dots (CQDs) with tunable bandgaps can make good use of solar energy, especially the infrared region. However, as the QD size increases, the energy level shrinking and surface facet evolution makes us reconsider the matching charge extraction contacts and the QD passivation strategy. Herein, different to the traditional sol‐gel ZnO layer, energy‐level aligned ZnO thin film from a magnetron sputtering method is adopted for electron extraction. In addition, a modified hybrid ligand recipe is developed for the facet passivation of large size QDs. As a result, the champion IRSC delivers an open circuit voltage of 0.49 V and a power conversion efficiency (PCE) of 10.47% under AM1.5 full‐spectrum illumination, and the certified PCE is over 10%. Especially the 1100 nm filtered efficiency achieves 1.23%. The obtained devices also show high storage stability. The present matched electron extraction and QD passivation strategies are expected to highly booster the IR conversion yield and promote the fast development of new conception QD optoelectronics.

Efficient Near‐Infrared PbS Quantum Dot Solar Cells Employing Hydrogenated In2O3 Transparent Electrode

“…IHO has a work function of 4.30 eV (Figure S4, Supporting Information) and other materials are referred from previous work. [10] The PCE of the optimized electrode device is improved by 1.2% from 9.95% to 11.15% as reported in Figure 3c and Table 2. The improvement of the device was attributed to the enhanced J SC from 34.2 mA cm −2 to 37.2 mA cm −2 (Figure 3c and Table 2).…”

“…IHO has a work function of 4.30 eV (Figure S4, Supporting Information) and other materials are referred from previous work. [ 10 ]…”

“…Notably, the Si‐filtered efficiency reached 1.25%, which is further improved on the results reported by Li et al (1.23%). [ 10 ] The proposed strategy in this work has also great potential for future transparent electronics and infrared photodetectors.…”

“…proposed a new ratio of hybrid ligands (PbI 2 :PbBr 2 = 4.6:1) to obtain an efficiency of 1.10% after Si‐filter. [ 9 ] Up to now, the record efficiency of 1300 nm PbS QD infrared solar cells under full AM 1.5G and Si‐filter spectrum were reported as 10.47% and 1.23% (Table S1), [ 10 ] respectively. Thus, it is possible to further increase the efficiency of Si solar cells by about 1.2%.…”

Rapid thermal annealing process for Se thin-film solar cells

“…35,36 More importantly, the energy level of the ZnO buffer layer is well-matched with that of the p-type Se thin film (Fig. 4c), 37 so the photogenerated carriers can be transported to the ZnO buffer layer and be collected by the electrode. In addition, during the RTA process, the sputtered ZnO thin film can induce a [ hkl ]-oriented ( l ≠ 0) Se thin film and benefit the transport of carriers as mentioned before.…”