In CZTSSe solar cells,a simple sodium-incorporation post-treatment method toward solution-processed Cu2Zn Sn S4precursor films is presented in this work.An ultrathin NaCl film is deposited on Cu2Zn Sn S4precursor film...In CZTSSe solar cells,a simple sodium-incorporation post-treatment method toward solution-processed Cu2Zn Sn S4precursor films is presented in this work.An ultrathin NaCl film is deposited on Cu2Zn Sn S4precursor films by spin-coating NaCl solution.In subsequent selenization process,the introduction of Na Cl is found to be benefacial for the formation of Cu2-xSe,which can further facilitate the element transportation,leading to dense and smooth CZTSSe films with large grains and less impurity Cu2Sn(S,Se)3phase.SIMS depth profiles confirm the gradient distribution of the sodium element in Na-doped absorbers.Photoluminescence spectra show that the introduction of appropriate sodium into the absorber can inhibit the band tail states.As high as 11.18% of power conversion efficiency(PCE)is achieved for the device treated with 5 mg mL^-1 NaCl solution,and an average efficiency of Na-doped devices is 10.71%,13%higher than that of the control groups(9.45%).Besides,the depletion width and the charge recombination lifetime can also have regular variation with sodium treatment.This work offers an easy modification method for high-quality Na-doped CZTSSe films and high-performance devices,in the meantime,it can also help to further understand the effects of sodium in CZTSSe solar cells.展开更多
金属氧化物光电极被认为在未来太阳能制氢方面具有广阔的前景,但由于其固有的载流子迁移率较低而面临着巨大挑战。铋酸铜(CuBi_(2)O_(4))光电阴极在光电化学水分解中具有很大的潜力和应用价值,是未来理想的光电阴极材料之一,本文采用喷...金属氧化物光电极被认为在未来太阳能制氢方面具有广阔的前景,但由于其固有的载流子迁移率较低而面临着巨大挑战。铋酸铜(CuBi_(2)O_(4))光电阴极在光电化学水分解中具有很大的潜力和应用价值,是未来理想的光电阴极材料之一,本文采用喷雾热解法制备CuBi_(2)O_(4)光电阴极,并通过形貌与能级调控实现了光电性能的突破。首先,通过在CuBi_(2)O_(4)光电阴极中进行Na+掺杂,低价态的Na+取代Bi^(3+)位点形成空穴中心,提升了载流子的迁移能力。与此同时,Na+元素的引入使所制备的CuBi_(2)O_(4)光电阴极具有多孔的纳米形貌,有效地缩短了光生载流子至表面的传输距离。其次,通过对Na+掺杂CuBi_(2)O_(4)光电阴极进行氧气煅烧(Na-CuBi_(2)O_(4)-O2),形成金属空位充当电子受体,减少了Na+掺杂引入的氧空位,从而提高空穴密度,进一步增强了电荷分离效率。这种策略使Na-CuBi_(2)O_(4)-O2光电阴极在0.6V vs.RHE时的光电流密度高达-2.83 mA·cm^(-2),是未经处理的CuBi_(2)O_(4)光电阴极的15倍(-0.18 mA cm^(-2))。结合时间分辨荧光光谱、开尔文探针力显微镜与光电化学研究,揭示了Na-CuBi_(2)O_(4)-O2光电阴极具有更高的载流子寿命与更高的表面光电压。这项工作利用元素掺杂与金属空位增强了CuBi_(2)O_(4)光电阴极的电荷分离和传输能力,实现了其光电性能的较大提升,对未来高性能光电阴极的制备具有指导意义。展开更多
基金financially supported by the National Natural Science Foundation of China (Nos. 51421002, 51627803, 91733301, 51761145042, 21501183, 51402348, 53872321, and 11874402)the Knowledge Innovation Program and the Strategic Priority Research Program (Grant XDB 12010400) of the Chinese Academy of Sciences
文摘In CZTSSe solar cells,a simple sodium-incorporation post-treatment method toward solution-processed Cu2Zn Sn S4precursor films is presented in this work.An ultrathin NaCl film is deposited on Cu2Zn Sn S4precursor films by spin-coating NaCl solution.In subsequent selenization process,the introduction of Na Cl is found to be benefacial for the formation of Cu2-xSe,which can further facilitate the element transportation,leading to dense and smooth CZTSSe films with large grains and less impurity Cu2Sn(S,Se)3phase.SIMS depth profiles confirm the gradient distribution of the sodium element in Na-doped absorbers.Photoluminescence spectra show that the introduction of appropriate sodium into the absorber can inhibit the band tail states.As high as 11.18% of power conversion efficiency(PCE)is achieved for the device treated with 5 mg mL^-1 NaCl solution,and an average efficiency of Na-doped devices is 10.71%,13%higher than that of the control groups(9.45%).Besides,the depletion width and the charge recombination lifetime can also have regular variation with sodium treatment.This work offers an easy modification method for high-quality Na-doped CZTSSe films and high-performance devices,in the meantime,it can also help to further understand the effects of sodium in CZTSSe solar cells.
文摘金属氧化物光电极被认为在未来太阳能制氢方面具有广阔的前景,但由于其固有的载流子迁移率较低而面临着巨大挑战。铋酸铜(CuBi_(2)O_(4))光电阴极在光电化学水分解中具有很大的潜力和应用价值,是未来理想的光电阴极材料之一,本文采用喷雾热解法制备CuBi_(2)O_(4)光电阴极,并通过形貌与能级调控实现了光电性能的突破。首先,通过在CuBi_(2)O_(4)光电阴极中进行Na+掺杂,低价态的Na+取代Bi^(3+)位点形成空穴中心,提升了载流子的迁移能力。与此同时,Na+元素的引入使所制备的CuBi_(2)O_(4)光电阴极具有多孔的纳米形貌,有效地缩短了光生载流子至表面的传输距离。其次,通过对Na+掺杂CuBi_(2)O_(4)光电阴极进行氧气煅烧(Na-CuBi_(2)O_(4)-O2),形成金属空位充当电子受体,减少了Na+掺杂引入的氧空位,从而提高空穴密度,进一步增强了电荷分离效率。这种策略使Na-CuBi_(2)O_(4)-O2光电阴极在0.6V vs.RHE时的光电流密度高达-2.83 mA·cm^(-2),是未经处理的CuBi_(2)O_(4)光电阴极的15倍(-0.18 mA cm^(-2))。结合时间分辨荧光光谱、开尔文探针力显微镜与光电化学研究,揭示了Na-CuBi_(2)O_(4)-O2光电阴极具有更高的载流子寿命与更高的表面光电压。这项工作利用元素掺杂与金属空位增强了CuBi_(2)O_(4)光电阴极的电荷分离和传输能力,实现了其光电性能的较大提升,对未来高性能光电阴极的制备具有指导意义。
