Sabari Girisun T C, Jeganathan C, Pavithra N, Anandan S
Nanophotonics Laboratory, School of Physics, Bharathidasan University, Tiruchirappalli, 620024, India.
Nanomaterials and Solar Energy Conversion Lab, Department of Chemistry, National Institute of Technology, Tiruchirappalli, 620015, India.
Eur Biophys J. 2019 Jan;48(1):61-71. doi: 10.1007/s00249-018-1331-1. Epub 2018 Sep 3.
Structurally modified bacteriorhodopsin (BR) was prepared by simple surfactant treatment using Cetyl trimethylammonium bromide (cationic; CTAB), Sodium dodecyl sulphate (anionic; SDS) and Triton X-100 (nonionic; TX-100). In the UV-visible absorption spectrum, the characteristic absorption band of native BR at 560 nm is hyperchromically (CTAB, due to induced aggregation), bathochromically (SDS, BR solubilisation and partial unfolding) and hypsochromically (TX-100, BR monomerizes) shifted after chemical treatment and the structural modifications were further confirmed by Raman spectra. Theoretical calculations based on optical absorption support an enhancement of BR optical and electrical conductivity via structural modification. Bio-sensitized solar cells (BSSCs) with structurally altered BR as sensitizer were fabricated and their photovoltaic performance was measured. We obtained the maximum short-circuit photocurrent and photoelectric conversion efficiency with TX-100-treated BR (0.93 mA cm, 0.47%), with a quasi-Fermi level and a 124-ms lifetime of photogenerated electrons in TX-100-treated BR-sensitized BSSCs, two times higher than that observed in BSSCs with native BR. A single-diode equivalent circuit model reveals favorable BSSC parameters such as high reverse saturation current (I = 55 nA), low series resistance (R = 22.9 Ω) and high shunt resistance (R = 3765.5 Ω) with TX-100-treated BR-based BSSCs. As TX-100 does not alter the BR carboxyl terminus during its monomerization, maximum anchoring to the BSSC occurs which results in enhanced photocurrent generation. Thus, monomerized BR-sensitized BSSCs with their excellent photovoltaic parameters suggest the possibility of replacing native BR with TX-100 BR and this opens up the possibility of reduced cost manufacture of bio-sensitized solar cells.
通过使用十六烷基三甲基溴化铵（阳离子型；CTAB）、十二烷基硫酸钠（阴离子型；SDS）和 Triton X - 100（非离子型；TX - 100）进行简单的表面活性剂处理，制备了结构修饰的细菌视紫红质（BR）。在紫外 - 可见吸收光谱中，天然 BR 在 560 nm 处的特征吸收带在化学处理后发生了增色（CTAB，由于诱导聚集）、红移（SDS，BR 溶解和部分展开）和蓝移（TX - 100，BR 单体化），并且通过拉曼光谱进一步证实了结构修饰。基于光吸收的理论计算支持通过结构修饰提高 BR 的光学和电导率。制备了以结构改变的 BR 作为敏化剂的生物敏化太阳能电池（BSSC），并测量了它们的光伏性能。我们发现用 TX - 100 处理的 BR 获得了最大短路光电流和光电转换效率（0.93 mA cm，0.47%），在 TX - 100 处理的 BR 敏化的 BSSC 中，光生电子的准费米能级和寿命为 124 ms，比天然 BR 敏化的 BSSC 中观察到的值高出两倍。单二极管等效电路模型显示，基于 TX - 100 处理的 BR 的 BSSC 具有良好的参数，如高反向饱和电流（I = 55 nA）、低串联电阻（R = 22.9 Ω）和高并联电阻（R = 3765.5 Ω）。由于 TX - 100 在其单体化过程中不会改变 BR 的羧基末端，因此与 BSSC 的锚定作用最大，从而导致光电流产生增强。因此，具有优异光伏参数的单体化 BR 敏化的 BSSC 表明有可能用 TX - 100 BR 替代天然 BR，这为降低生物敏化太阳能电池的制造成本开辟了可能性。
