Band-structure tailoring and surface passivation for highly efficient near-infrared responsive PbS quantum dot photovoltaics
| Autor: | Xiaoli Mao, Huier Guo, Lei Wan, Jinzhang Xu, Haihong Niu, Ru Zhou, Fengwei Ji, Guozhong Cao |
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| Rok vydání: | 2016 |
| Předmět: |
Materials science
Passivation Renewable Energy Sustainability and the Environment business.industry Band gap Exciton Energy conversion efficiency Energy Engineering and Power Technology Nanotechnology 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences law.invention Quantum dot law Photovoltaics Solar cell Optoelectronics Electrical and Electronic Engineering Physical and Theoretical Chemistry 0210 nano-technology Electronic band structure business |
| Zdroj: | Journal of Power Sources. 333:107-117 |
| ISSN: | 0378-7753 |
| DOI: | 10.1016/j.jpowsour.2016.09.160 |
| Popis: | PbS is a promising light harvester for near-infrared (NIR) responsive quantum dot (QD) photovoltaics due to its narrow bulk band gap (0.41 eV) and large exciton Bohr radius (18 nm). However, the relatively low conduction band (CB) and high-density surface defects of PbS as two major drawbacks for its use in solar cells severely hamper the photovoltaic performance enhancement. In this work, a modified solution-based successive ionic layer adsorption and reaction (SILAR) utilizing mixed cationic precursors of Pb2+ and Cd2+ is explored, and such a scheme offers two benefits, band-structure tailoring and surface passivation. In-situ deposited CdS suppresses the excessive growth of PbS in the mesopores, thereby facilitating the favorable electron injection from PbS to TiO2 in view of the up-shifted CB level of QDs; the intimate interpenetration of two sulfides with each other leads to superior passivation of trap state defects on PbS, which suppresses the interfacial charge recombination. With the construction of photovoltaics based on such a hybrid (Pb,Cd)S/CdS configuration, impressive power conversion efficiency up to 4.08% has been reached, outperforming that of the conventional PbS/CdS pattern (2.95%). This work highlights the great importance of band-structure tailoring and surface passivation for constructing highly efficient PbS QD photovoltaics. |
| Databáze: | OpenAIRE |
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