Thanihaichelvan Murugathas, Kodikara Minidu Manoranjana Punya Sri, Ravirajan Punniyamoorthy, Velauthapillai Dhayalan
Department of Physics, Faculty of Science, University of Jaffna, Jaffna 40000, Sri Lanka.
Faculty of Engineering, Campus Bergen, Western Norway University of Applied Sciences, P.O. Box 7030, 5020 Bergen, Norway.
Polymers (Basel). 2017 Sep 22;9(10):467. doi: 10.3390/polym9100467.
This work reports the effect of co-sensitization of nanoporous titanium dioxide using Cadmium Sulfide (CdS) and poly(3-hexylthiophene) (P3HT) on the performance of hybrid solar cells. CdS nanolayer with different thicknesses was grown on Titanium Dioxide (TiO₂) nanoparticles by chemical bath deposition technique with varying deposition times. Both atomic force microscopy (AFM) and UV⁻Vis⁻NIR spectroscopy measurements of TiO₂ electrode sensitized with and without CdS layer confirm that the existence of CdS layer on TiO₂ nanoparticles. AFM images of CdS-coated TiO₂ nanoparticles show that the surface roughness of the TiO₂ nanoparticle samples decreases with increasing CdS deposition times. Current density⁻voltage and external quantum efficiency (EQE) measurements were carried out for corresponding solar cells. Both short circuit current density () and fill factor were optimized at the CdS deposition time of 12 min. On the other hand, a steady and continuous increment in the open circuit voltage () was observed with increasing CdS deposition time and increased up to 0.81 V when the deposition time was 24 min. This may be attributed to the increased gradual separation of P3HT and TiO₂ phases and their isolation at the interfaces. The higher of 0.81 V was due to the higher built-in voltage at the CdS⁻P3HT interface when compared to that at the TiO₂⁻P3HT interface. Optimized nanoporous TiO₂ solar cells with CdS and P3HT co-sensitizers showed external quantum efficiency (EQE) of over 40% and 80% at the wavelengths corresponding to strong absorption of the polymer and CdS, respectively. The cells showed an overall average efficiency of over 2.4% under the illumination of 70 mW/cm² at AM 1.5 condition.
本工作报道了使用硫化镉（CdS）和聚（3-己基噻吩）（P3HT）对纳米多孔二氧化钛进行共敏化对混合太阳能电池性能的影响。通过化学浴沉积技术，在不同沉积时间下，在二氧化钛（TiO₂）纳米颗粒上生长了不同厚度的CdS纳米层。对有和没有CdS层敏化的TiO₂电极进行原子力显微镜（AFM）和紫外-可见-近红外光谱测量，证实了TiO₂纳米颗粒上CdS层的存在。CdS包覆的TiO₂纳米颗粒的AFM图像表明，TiO₂纳米颗粒样品的表面粗糙度随着CdS沉积时间的增加而降低。对相应的太阳能电池进行了电流密度-电压和外量子效率（EQE）测量。在CdS沉积时间为12分钟时，短路电流密度（）和填充因子均得到优化。另一方面，随着CdS沉积时间的增加，开路电压（）稳定持续增加，当沉积时间为24分钟时，开路电压增加到0.81V。这可能归因于P3HT和TiO₂相的逐渐分离增加以及它们在界面处的隔离。0.81V的较高开路电压是由于CdS-P3HT界面处的内建电压高于TiO₂-P3HT界面处的内建电压。具有CdS和P3HT共敏化剂的优化纳米多孔TiO₂太阳能电池在对应于聚合物和CdS强吸收的波长处分别显示出超过40%和80%的外量子效率（EQE）。在AM 1.5条件下70 mW/cm²的光照下，这些电池的整体平均效率超过2.4%。
