Okello Alex, Owuor Brian Owino, Namukobe Jane, Okello Denis, Mwabora Julius
Department of Physics, Makerere University, P.O. Box 7062, Kampala, Uganda.
Department of Physics, University of Nairobi, P.O. Box 30197-00100, Nairobi, Kenya.
Heliyon. 2021 Mar 24;7(3):e06571. doi: 10.1016/j.heliyon.2021.e06571. eCollection 2021 Mar.
The influence of concentration of anthocyanins in dye sensitized solar cells (DSSC) has been investigated, with focus on how concentration influence electron transport. The influence on electron transport was then linked to solar cell performance. Anthocyanins were extracted from fresh flowers of using methanol acidified with 0.5% trifluoracetic acid, concentrated using a rotary evaporator and partitioned against ethyl acetate. Concentration of the anthocyanins was determined using Keracyanin Chloride as a standard. DSSC were fabricated using Titanium dioxide as anode, anthocyanins as sensitizers and Platinum as counter electrode material. Titanium dioxide was deposited on Fluorine doped Tin oxide glass substrate using slot coating method. Platinum was deposited on FTO glass substrate using a brush previously dipped in plastisol precursor, and annealed at C for 20 min to activate Platinum. Dye sensitized solar cells were assembled using anthocyanins at varying concentrations. Performance parameters of the solar cells were measured using a solar simulator which was fitted with digital source meter. Electron transport parameters were studied using electrochemical impedance spectroscopy (EIS). Open circuit voltage, short circuit current and fill factor were observed to increase with concentration of anthocyanins. The increase in solar cell performance was attributed to increase in charge density which led more charges being available for transported to solar cell contacts. The increased charge resulted in a negative shift in Fermi level of electrons in the conduction band of TiO. The shift in Fermi level resulted into an increase in open circuit voltage and the overall solar cell performance. EIS studies revealed increase in recombination resistance with concentration of anthocyanins. The increase in recombination resistance was found to be related to increase in electron density, and hence the shift in the Fermi level of electrons in the conduction band of TiO.
研究了染料敏化太阳能电池（DSSC）中花青素浓度的影响，重点关注浓度如何影响电子传输。然后将对电子传输的影响与太阳能电池性能联系起来。用0.5%三氟乙酸酸化的甲醇从新鲜花朵中提取花青素，用旋转蒸发仪浓缩并与乙酸乙酯进行分配。以氯化矢车菊素为标准测定花青素的浓度。使用二氧化钛作为阳极、花青素作为敏化剂、铂作为对电极材料制备DSSC。采用狭缝涂布法将二氧化钛沉积在氟掺杂氧化锡玻璃基板上。使用预先浸入增塑溶胶前驱体的刷子将铂沉积在FTO玻璃基板上，并在[具体温度]下退火20分钟以活化铂。使用不同浓度的花青素组装染料敏化太阳能电池。使用配备数字源表的太阳能模拟器测量太阳能电池的性能参数。使用电化学阻抗谱（EIS）研究电子传输参数。观察到开路电压、短路电流和填充因子随花青素浓度的增加而增加。太阳能电池性能的提高归因于电荷密度的增加，这使得更多电荷可用于传输到太阳能电池触点。电荷的增加导致TiO导带中电子费米能级的负移。费米能级的移动导致开路电压和整体太阳能电池性能的增加。EIS研究表明，复合电阻随花青素浓度的增加而增加。发现复合电阻的增加与电子密度的增加有关，因此与TiO导带中电子费米能级的移动有关。
