超越传统光伏:弱光环境下可印刷介观钙钛矿太阳能电池光电特性

Beyond traditional photovoltaics:Photoelectric characteristics of printable mesoscopic perovskite solar cells under low light intensities

钙钛矿太阳能电池(perovskite solar cell,PSC)近年来发展十分迅速,被认为是下一代光伏技术中最有前景的候选者之一.其中,基于三层介孔膜结构的可印刷介观PSC以其廉价的原材料、简单的制备工艺以及良好的器件稳定性获得了广泛关注.本文测试了可印刷介观PSC小型模组(10 cm×10 cm)在不同光照强度条件下的光电性能,并与商用的单晶硅(crystalline silicon,c-Si)、多晶硅(polycrystalline silicon,poly-Si)和碲化镉(CdTe)太阳能电池进行了对比.结果表明,随着光照强度的降低,c-Si、poly-Si、CdTe太阳能电池的光电转换效率(power conversion efficiency,PCE)均出现了不同程度的下降,而可印刷介观PSC的PCE几乎呈线性增加.当光照强度低于0.3个标准太阳光(30 mW cm^(–2))时,可印刷介观PSC已经开始展现出一定的光电转换效率优势;当光照强度进一步降低至标准室内弱光条件(1000 lux,约0.3 mW cm^(–2))时,其PCE可达19.83%,高于其他商用太阳能电池.PSC在弱光环境下展现出的优异性能为进一步扩展其在室内等场景的应用奠定了良好基础,这些潜在的新兴应用领域为PSC的商业化和大规模生产提供了多种应用空间.

Perovskite solar cells(PSCs)are considered as one of the most promising candidates for next-generation photovoltaic technology due to their rapid development in recent years.Among them,the printable mesoscopic PSC based on the triple mesoporous layers has attracted wide attention for the advantages of low-cost raw materials,simple manufacturing process and excellent long-term stability.At present,the studies are focused on the applications of PSCs under one standard sunlight(1.0 sun,100 m W cm^(–2)),while neglecting the applications under low light intensities.In this work,we demonstrate that PSCs have outstanding performance under low-intensity illumination,and can be applied for indoor applications,for which traditional PV technologies can hardly compete with.Previously,we have reported printable mesoscopic PSC mini-modules(substrate area 10 cm×10 cm)with an efficiency of^10%under one sun illumination and outstanding stability under various conditions.Herein,we investigated the performance of four small modules under the illumination of different light intensities(1.0–0.05 sun),including PSC,monocrystalline silicon(c-Si),polycrystalline silicon(poly-Si)and cadmium telluride(Cd Te)solar cells.When the light intensity decreased from 1.0 to 0.05 sun,we observed a drop of photoelectric conversion efficiency(PCE)of c-Si,poly-Si and Cd Te solar cells at various rates.On the contrary,we found that the PCE of PSC mini-modules increased linearly when light intensity decreased.The PCE of the PSC mini-modules was higher than that of poly-Si and Cd Te solar cells when the light intensity was under 0.3 sun.Under a very low light intensity of 0.05 sun,the PCE of PSC module was higher than that of all other solar cells.It can be foreseen in the near future that the PCE of PSC modules will reach a much higher value.According to this linear upward trend,if the efficiency of PSC mini-modules reaches 12%at 1.0 sun,it will completely surpass the PCE of c-Si,poly-Si and Cd Te solar cells under the light intensity less than 0.5 sun.Furthermore,if the efficiency of PSC mini-modules reaches 15%at 1.0 sun,it will completely surpass the PCE of c-Si,poly-Si and Cd Te solar cells under most intensity illuminations,showing huge potential in various application scenarios.For practical applications,the output power density(Pmax)of different solar cells should be taken into account.We introduced ratios of the Pmaxat 0.1 sun to the Pmaxat 1 sun(Pmax,0.1sun/Pmax,1sun)and the Pmaxat 0.05 sun to the Pmaxat 1 sun(Pmax,0.05sun/Pmax,1sun)to compare the changes in performance from 1.0 to 0.1 and 0.05 sun for all these solar cells.The PSC showed the highest ratio among all the solar cells.According to the equivalent circuit model of solar cells,the dark current of different devices were characterized which is related to the leakage current(Jsh)in the device.In general,the magnitude of the leakage current has the order:PSC<CdTe<c-Si<poly-Si.The shunt resistances(Rsh)of four types of solar cells were calculated as 7.5×10^(8),5.90×10^(8),7.84×10^(7),4.95×10^(5)〉Ωcm^(2),which have the reverse order of Jsh.For cells with high Jsh,the PSC mini-modules had less loss caused by the Rsh.This result explained why the FF of PSC mini-modules increased when the light intensity decreased.When the light intensity was further reduced to the standard indoor low light conditions(1000 lux,about 0.3 mW cm^(-2)),printable mesoscopic PSC had the highest PCE of 19.83%and 17.61%at two different color temperatures of 6500 and 2700 K,respectively.