High Efficiency of Dye-Sensitized Solar Cells Based on Ruthenium and Metal-Free Dyes

Abstract

A Triazolo- isoquinoline series dye which has an excellent photoelectric conversion 4L nature has been invented It complements the deficiency of organometallic dye absorption in the UV region A total of 4L and N719 absorption were used had improved the dye-sensitized photoelectric conversion efficiency from 4 49% to 5 15% The overall conversion efficiency had actually increased of about 15% By using the pure component N719 that analyzed using eight Mesoporous with four scattering as the cablibration standard the ratio of N719 with 4L was control to observe the photoelectric effect of 4L near the ultra-violet region The pure 4L showed weak sensitizer effect with only 1 14% photoelectric conversion efficiency reached Main causes of this result was firstly the narrow absorption range that made short-circuit current only obtained 3 25 (mA/cm2) and secondly the chemical structural characteristics of this relationship decrease the difference between the dye molecule's potential and I-/I3- potential d and resulted a decrease of Voc down to 0 58V deterioration of FF also followed by the decline of η When the ratio of N719 and 4L would be 4:1 resulted a potential drop in 4L to 0 7V that caused by the absorption conditions happened in open circuit voltage in the same time as the presence of 4L has solved the absorption problem of N719 near ultraviolet region the short-circuit current is increased up to 10 68 (mA/cm2) This result also improve the the overall efficiency of about 15% where the photoelectric conversion efficiency increase from pure N719 4 49% into N719 with 4L of absorption 5 15% Consequently IPCE spectrum showed an IPCE value of about 40% for N719 in the 350-500mm but after 4L was adding in IPCE value raised to 65% This could explain why N719 with 4L of absorption has greater conversion efficiency compare to pure N719 Besides the concentration of N719 and 4L were controlled into absorption conditions ratio 1:1 The 4L obtained a substantial increase in the absorption capacity which resulting in severe decline of Voc value 0 67V compare to the ratio of N719 and 4L would be 4:1 Hence the conversion efficiency was even weaker than pure N719 only 4 31% obtained Moreover showed an increase of IPCE values in the range of 350-500mm way up to 82% but absorption decreased when it is in the range of 550-750mm this indicates that N719 has weak absorption on N719 and 4L were controlled into absorption conditions ratio 1:1 where conversion efficiency of N719 and 4L absorption conditions ratio 1:1 are the weakest if were to compare to pure 4L and the ratio of N719 and 4L would be 4:1 In short 4L was synthesized successfully Although there is a red shift found in 4RL absorption spectrum the conversion efficiency of 4RL is still low and N719 has greater overlapping in absorption spectra This so the reason that 4L and N719 were chosen in this sensitized experiment in 4:1 molar degree agricultural conditions the overall effect of photoelectric conversion could reach 5 15% due to the great absorption properties of 4L in the near-UV region This finding also provides a new design direction in dye industry for the future

Date of Award	2015 Jan 30
Original language	English
Supervisor	Wen-Shi Lee (Supervisor)