Department of Chemistry, Sardar Patel University, Vallabh Vidyanagar - 388 120, Gujarat, India.
Nanoscale. 2017 Oct 26;9(41):15949-15957. doi: 10.1039/c7nr06128e.
A novel saturated heterocyclic organic ionic crystal, piperidinium iodide (PiHI), is synthesized by a facile route and applied as a solid electrolyte in Dye Sensitized Solar Cells (ss-DSSCs). Upon addition of a small quantity of iodine, PiHI self-assembles into a 1D lamellar micro crystalline structure that shows anisotropic conductivity. The two-component PiHI was characterized by using electrochemical impedance spectroscopy, cyclic voltammetry, steady state voltammetry, FT-IR, and Raman spectroscopy. Wide angle X-ray diffraction (XRD) measurement confirms the presence of long range 1D lamellar channels that pave the way for the diffusion of the redox couple I/I and exhibit high anisotropic conductivity. The ionic conductivity of 1D PiHI (with I) aligned perpendicular to the electrode, σ (15.46 mS cm), is 1.5 times higher than that aligned parallel to the electrode σ = 10.32 mS cm. The ss-DSSC devices with these self-assembled ordered ionic crystals with a carbazole based sensitizer (SK1) achieved a power conversion efficiency (PCE) of 4.2% and 5.2% for ∥ and ⊥ arrangement, respectively. The reported PCEs are better than that obtained from a classical liquid electrolyte with SK1 sensitizers. The electron kinetics at various interfaces of ss-DSSC devices was evaluated using Electrochemical Impedance Spectroscopy (EIS) measurements. The presence of a saturated cyclic structure promotes close packing through H-bonding and electrostatic interactions, which make ss-DSSC devices more stable up to 600 h under illumination of 1 sun.
一种新型的饱和杂环有机离子晶体，碘化哌啶（PiHI），通过简便的方法合成，并作为固态电解质应用于染料敏化太阳能电池（ss-DSSC）中。在添加少量碘后，PiHI 自组装成一维层状微晶结构，表现出各向异性的导电性。通过电化学阻抗谱、循环伏安法、稳态伏安法、FT-IR 和拉曼光谱对双组分 PiHI 进行了表征。广角 X 射线衍射（XRD）测量证实存在长程一维层状通道，为氧化还原对 I/I 的扩散铺平了道路，并表现出高各向异性导电性。垂直于电极排列的一维 PiHI（含 I）的离子电导率 σ（15.46 mS cm）比平行于电极排列的 σ（10.32 mS cm）高 1.5 倍。具有咔唑基敏化剂（SK1）的这些自组装有序离子晶体的 ss-DSSC 器件分别获得了 4.2%和 5.2%的功率转换效率（PCE）。报道的 PCE 优于使用 SK1 敏化剂的经典液体电解质获得的 PCE。使用电化学阻抗谱（EIS）测量评估了 ss-DSSC 器件中各种界面的电子动力学。饱和环状结构的存在通过氢键和静电相互作用促进紧密堆积，这使得 ss-DSSC 器件在 1 个太阳照射下稳定 600 小时以上。
