宽光谱高效硅基薄膜太阳电池的基础研究报告

介绍高绒度MOCVD-ZnO:B透明导电薄膜用作非晶硅太阳电池前电极、非晶硅太阳电池BZO/p-a-SiC:H接触特性改善、非晶硅界面缓冲层对非晶硅锗电池性能的影响以及非晶硅锗电池性能的调控等方面的研究内容及结果。首先我们将自行研制的具有优异陷光效果的掺硼氧化锌BZO用作p-i-n型非晶硅太阳电池的前电极,并且将传统商业用U型掺氟二氧化锡FTO作为对比电极。结果表明相对FTO电池,尽管BZO电池的电流优势明显,但当本征层厚度较薄时其Voc和FF却较差。原因是相对于表面较为平滑的FTO,BZO表面呈大类金字塔的绒面结构会在本征层生长过程中触发阴影效应,形成大量的高缺陷材料区和漏电沟道,进而恶化电池的Voc和FF。在不修饰BZO表面形貌的情况下,通过调节非晶硅本征层的沉积温度来消弱BZO高绒度表面引起的这种不利影响,改善后的电池Voc和FF均有提升。在仅有Al背电极的情况下,当本征层厚度为200 nm时,BZO前电极非晶硅太阳电池效率达7.34%。其次,我们采用重掺杂的p型微晶硅来改善前电极掺硼氧化锌(ZnO:B)和窗口层p型非晶硅碳(p-aSiC)之间的非欧姆接触特性。通过优化插入层p型微晶硅的沉积参数(氢稀释比H_2/SiH_4、硼掺杂比B_2H_6/SiH_4)获得了较薄厚度下(20 nm)暗电导率高达4.2 S/cm的p型微晶硅材料。在本征层厚度约为150 nm,仅采用Al背反射电极的情况下,获得了效率6.37%的非晶硅顶电池,开路电压Voc和填充因子FF均较无插入层的电池有大幅提升。第三,采用射频等离子体增强化学气相沉积(RF-PECVD)技术,进行了非晶硅锗薄膜太阳电池的研究。针对非晶硅锗薄膜材料的本身特性,通过调控硅锗合金中硅锗的比例,实现了对硅锗薄膜太阳电池中开路电压和短路电流密度的分别控制。借助于本征层硅锗材料帯隙梯度的设计,获得了可有效用于多结叠层电池中的非晶硅锗电池。最后,介绍了针对非晶硅锗电池本征层高锗含量时界面带隙失配以及高界面缺陷密度造成电池开路电压和填充因子下降的问题,通过在P/I界面插入具有合适带隙的非晶硅缓冲层,不仅有效缓和了带隙失配,降低界面复合,同时也通过降低界面缺陷密度,改善内建电场分布从而提高了电池的收集效率。进一步引入I/N界面缓冲层以及对非晶硅锗本征层进行能带梯度设计,在仅采用Al背电极时,单结非晶硅锗电池转换效率达8.72%。总之,通过以上优化措施,最后获得了效率为14.06%的非晶硅/非晶硅锗/微晶硅三结叠层太阳电池。

A Sacrificial Layer Etching Method Applied in Surface Micromachining Using Agitated BHF and Glycerol Solution

A modified buffered-HF solution with NH4 F ： glycerol ： HF（4 ： 2 ： 1）is studied. With the implementation of a heating and agitating mechanism, this method is applied in a sacrificial layer etching scheme that increases the selectivity between silicon dioxide and aluminum. The etching rates of SiO2 and Al as a function of solution temperature are determined. Moreover,the effects of adding glycerol and agitating the etchant are examined and compared with this method. Finally, this method is tested on an actual device, and its efficiency is scrutinized.

Enhancement of the efficiency and stability of planar p-i-n perovskite solar cells via incorporation of an amine-modified fullerene derivative as a cathode buffer layer

A methanol-soluble diamine-modified fullerene derivative(denoted as PCBDANI)was applied as an efficient cathode buffer layer(CBL)in planar p-i-n perovskite solar cells(pero-SCs)based on the CH_3NH_3PbI_(3-x)Cl_x absorber.The device with PCBDANI single CBL exhibited significantly improved performance with a power conversion efficiency(PCE)of 15.45%,which is approximately17%higher than that of the control device without the CBL.The dramatic improvement in PCE can be attributed to the formation of an interfacial dipole at the PCBM/Al interface originating from the amine functional group and the suppression of interfacial recombinationby the PCBDANI interlayer.To further improve the PCE of pero-SCs,PCBDANI/LiF double CBLs were introduced between PCBM and the top Al electrode.An impressive PCE of 15.71%was achieved,which is somewhat higher than that of the devices with LiF or PCBDANI single CBL.Besides the PCE,the long-term stability of the device with PCBDANI/LiF double CBLs is also superior to that of the device with LiF single CBL.