Improving PbS Quantum Dot Solar Cell Power Conversion Efficiency to an NREL-Certified 4.4% (Fact Sheet)

关键词: ANODES;    BENDING;    DIPOLES;    EFFICIENCY;    ELECTRODES;    HETEROJUNCTIONS;    LEAD SULFIDES;    MOLYBDENUM OXIDES;    NATIONAL RENEWABLE ENERGY LABORATORY;    OXIDES;    PERFORMANCE;    QUANTUM DOTS;    SOLAR CELLS;    TRANSITION ELEMENTS;    TRANSPORT;    VALENCE;    VANADIUM OXIDES NREL HIGHLIGHT;    QUANTUM DOT;    QD;    TRANSITION METAL OXIDE;    TMO;    Chemical and Material Sciences;   

DOI  :  10.2172/1033445
RP-ID  :  NREL/FS-5900-53382
PID  :  OSTI ID: 1033445
Others  :  TRN: US201202%%879

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来源: SciTech Connect

【 摘 要 】

Transition metal oxide improves overall efficiency and maintains performance with inexpensive metals. A research team at the National Renewable Energy Laboratory (NREL) has demonstrated that inserting a transition metal oxide (TMO) between the lead sulfide (PbS) quantum dot (QD) layer and the metal electrode eliminates the Schottky barrier that impedes efficient hole extraction and thereby improves the overall conversion efficiency. This allows for inexpensive metals such as Al to be employed without loss of performance. n-type TMOs consisting of molybdenum oxide (MoO{sub x}) and vanadium oxide (V{sub 2}O{sub x}) were used as an efficient hole extraction layer (HEL) in heterojunction ZnO/PbS QD solar cells. A 4.4% NREL-certified device was reported based on the MoO{sub x} HEL with Al as the back contact material, representing a more than 65% efficiency improvement compared with the case of Au contacting the PbS QD layer directly. The team finds the acting mechanism of the HEL to be a dipole formed at the MoO{sub x} and PbS interface, which enhances band bending to allow efficient hole extraction from the valence band of the PbS layer by MoO{sub x}. The carrier transport to the metal anode is likely enhanced through shallow gap states in the MoO{sub x} layer.