Inorganic CsPbI₃ Perovskite Coating on PbS Quantum Dot for Highly Efficient and Stable Infrared Light Converting Solar Cells

Abstract

Solution‐processed colloidal quantum dot (CQD) solar cells harvesting the infrared part of the solar spectrum are especially interesting for future use in semitransparent windows or multilayer solar cells. To improve the device power conversion efficiency (PCE) and stability of the solar cells, surface passivation of the quantum dots is vital in the research of CQD solar cells. Herein, inorganic CsPbI3 perovskite (CsPbI3‐P) coating on PbS CQDs with a low‐temperature, solution‐processed approach is reported. The PbS CQD solar cell with CsPbI3‐P coating gives a high PCE of 10.5% and exhibits remarkable stability both under long‐term constant illumination and storage under ambient conditions. Detailed characterization and analysis reveal improved passivation of the PbS CQDs with the CsPbI3‐P coating, and the results suggest that the lattice coherence between CsPbI3‐P and PbS results in epitaxial induced growth of the CsPbI3‐P coating. The improved passivation significantly diminishes the sub‐bandgap trap‐state assisted recombination, leading to improved charge collection and therefore higher photovoltaic performance. This work therefore provides important insight to improve the CQD passivation by coating with an inorganic perovskite ligand for photovoltaics or other optoelectronic applications.

Highly Stabilized Quantum Dot Ink for Efficient Infrared Light Absorbing Solar Cells

“…[28,61] The OA covered QD in octane (≈8 mg mL −1 ) was mixed with the DMF solvent containing 0.1 m PbI 2 , 0.02 m PbBr 2 , and 0.04 m ammonium acetate. [28,61] The OA covered QD in octane (≈8 mg mL −1 ) was mixed with the DMF solvent containing 0.1 m PbI 2 , 0.02 m PbBr 2 , and 0.04 m ammonium acetate.…”

“…[28] The PL decay was fitted using the following equation Fluorolog spectrophotometer (HORIBA JOBIN YVON) was used for the measurement of steadystate PL spectrum and the sample was excited with an excitation at 550 nm.…”

“…I 3d core level in Figure 2f shows a much stronger signal for PbS-AI QDs in relation to PbS-PbX 2 QDs, indicating higher iodine ion incorporation in the PbS-AI QDs than that of in PbS-PbX 2 QD counterpart. [28,46] When the spectra are normalized to the underlayer PbS S 2p signal, Pb 4f intensities are nearly equivalent for both PbS-PbX 2 and PbS-AI QD samples indicating a similar thickness of the overlayer. [44,45] The Pb 4f peak (Figure 2g) shifts slightly to higher binding energy (BE) for PbS-PbX 2 QDs (138.1 eV) than that of PbS-AI QDs (137.9 eV) and both signals are indicative of a Pb 2+ oxidation state.…”

“…Therefore, the QD ink was spin-coated on the glass/ ITO/AZO substrate, which is applied for the fabrication of solar cell devices. [26,28] It is worthy to note that the surface topography largely affects the optical interference in a QDSC, thus affecting the device photovoltaic performance. It can be seen that the QD film looks quite smooth with a dark color and the film exhibits mirror-like properties.…”

Extremely lightweight and ultra-flexible infrared light-converting quantum dot solar cells with high power-per-weight output using a solution-processed bending durable silver nanowire-based electrode

“…The PbS CQDs capped with oleic acid ligand were synthesized using a hot injection method according to a previous report. [52][53][54][55] Solution-phase ligand exchange was performed prior to the CQD solid film deposition according to the literature with modification. 29 Briefly, the CQD octane solution (B10 mg mL…”