Interfaces of high-efficiency kesterite Cu₂ZnSnS(e)₄thin film solar cells

Abstract

Cu 2 ZnSnS(e) 4 (CZTS(e)) solar cells have attracted much attention due to the elemental abundance and the nontoxicity. However, the record efficiency of 12.6% for Cu 2 ZnSn(S,Se) 4 (CZTSSe) solar cells is much lower than that of Cu(In,Ga)Se 2 (CIGS) solar cells. One crucial reason is the recombination at interfaces. In recent years, large amount investigations have been done to analyze the interfacial problems and improve the interfacial properties via a variety of methods. This paper gives a review of progresses on interfaces of CZTS(e) solar cells, including: (i) the band alignment optimization at buffer/CZTS(e) interface, (ii) tailoring the thickness of MoS(e) 2 interfacial layers between CZTS(e) absorber and Mo back contact, (iii) the passivation of rear interface, (iv) the passivation of front interface, and (v) the etching of secondary phases.

Efficient Optimization of the Performance of Mn2+‐Doped Kesterite Solar Cell: Machine Learning Aided Synthesis of High Efficient Cu2(Mn,Zn)Sn(S,Se)4 Solar Cells

“…Thin film solar cells Cu 2 ZnSnS 4 (CZTS) and Cu 2 ZnSnSe 4 (CZTSe) are prospective substitutes for Cu(In,Ga)Se 2 (CIGS) due to the composition elements of their absorber materials are non‐toxic and earth abundant. Up to now, the champion efficiency of CZTSSe solar cells is still 12.6%, which is mainly because of the large V OC deficit ( E g / q ‐ V OC ) . One of the important factors for low efficiency in CZTSSe is cationic disorder .…”

Room‐Temperature Surface Sulfurization for High‐Performance Kesterite CZTSe Solar Cells

“…Kesterite‐structured Cu 2 ZnSn(S,Se) 4 (CZTSSe) has been studied extensively because of its earth‐abundance, low toxicity, and high absorption coefficient . To date, the efficiency of CZTSSe solar cells has reached 12.7%, which is still far lower than the best efficiency of CIGS solar cells (22.9%) .…”

Interface engineering of p-n heterojunction for kesterite photovoltaics: A progress review

“…Large open-circuit voltage deficit (V oc ) (less than 60% of the maximum achievable V ocmax) and relatively low fill factor (FF) (about 70%) are common problems in all reported kesterite solar cells, which is the present bottleneck limiting efficiency [4,5,32,33,6,15,[26][27][28][29][30][31]. The limited V oc and FF in kesterite are likely due to two critical aspects: defect-assisted recombination in bulk and interface induced recombination at the heterojunction [4][5][6][7]34,35]. The antisite defects associated with band tailing contribute to bulk recombination that is generally believed to be responsible for the V oc deficit.…”

“…[4][5][6]36] for information about bulk recombination. In addition, the recombination at the pn heterojunction caused by mismatched band alignment and unpassivated interface defects is highly detrimental to efficiency, as efficient operation of the solar cell depends on an effective charge separation at the heterojunction [35,[37][38][39]. In kesterite, CdS as a conventional buffer exhibits a poor band alignment with high bandgap CZTS, while the formation of detrimental point defects are prevalent in CZTSSe near the interface and within the bulk due to their low formation energy [36,37].…”