Lead Sulfide Cathode for Quantum Dot Solar Cells: Electrosynthesis and Characterization

• Published in: Journal of electronic materials 2017, Vol.46 (1), p.274-281
• Main Authors: Van Le, Nghiem, Nguyen, Hoang Thai, Le, Hai Viet, Nguyen, Thoa Thi Phuong
• Format: Article
• Language: English
• Subjects: Adsorption; Cadmium; Characterization and Evaluation of Materials; Chemistry and Materials Science; Dyes; Electrodes; Electrolytes; Electronics and Microelectronics; Ethanol; Glass substrates; Instrumentation; Materials Science; Nitrates; Optical and Electronic Materials; Physical chemistry; Quantum dots; Scanning electron microscopy; Sodium; Solid State Physics; Voltammetry
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-016-4844-3

Deposition of lead sulfide (PbS) nanocrystalline thin films onto conducting fluorine-doped tin oxide (FTO) glass has been performed by cyclic voltammetry (CV) in 1.5 mM solution of lead nitrate and sodium thiosulfate at 100 mV s −1 scan rate in the potential range of −1.0 V to 0.0 V versus saturated calomel electrode. X-ray diffraction analysis and scanning electron microscopy revealed formation of cubic PbS crystals with size of 100 nm to 150 nm after 50 cycles. High electrocatalytic activity of the synthesized PbS film for the S 2− /S n 2− redox couple, used as a mediator for quantum dot solar cells (QDSCs), was demonstrated by electrochemical impedance spectroscopy and CV measurements. The prepared PbS/FTO was used as a counterelectrode to fabricate PbS-QDSCs with a photoanode consisting of CdS/CdSe quantum dots adsorbed on mesoporous TiO 2 film and a polysulfide solution electrolyte. The performance of the PbS-QDSC was compared with a QDSC with a platinum counterelectrode (Pt-QDSC). It was found that, using the same fabrication conditions, the performance of the PbS-QDSC was better than that of the Pt-QDSC. At 1 sun (100 mW cm −2 ) simulated light, average energy conversion efficiency of 2.14%, short-circuit current of 9.22 mA cm −2 , open-circuit potential of 0.50 V, and fill factor of 0.47 were achieved by the fabricated PbS-QDSC.