The present research study focuses upon the synthesis, characterization, and performances of optoelectronic properties of organic-inorganic (hybrid) ZnO based dye sensitized solar cells. Initially, polymer dye
Currently, different types of photovoltaic materials, for example, organic dyes, inorganic semiconductor nanoparticles, conducting polymers, and their combinations, have been prepared for utilization in optimal optoelectronic and photovoltaic applications. The combination of organic and inorganic semiconductor material fabricates the hybrid nature of the resulting material [
Schematic of polymer dye capped ZnO based DSSC.
This section deeply focuses on the synthesis procedure and structural characteristics of polymer dye
For synthesis process, all the chemical materials were purchased from a commercial dealer and were used without further purification. 1H NMR (nuclear magnetic resonance) and 13C NMR (nuclear magnetic resonance) spectra were recorded on Avance-II (Bruker) instrument, which was operated at 400 MHz for 1H NMR. The CHN (carbon, hydrogen, and nitrogen) analysis was performed on PerkinElmer 2400 CHN Elemental Analyzer. For cation recognition studies, the UV-Vis absorption spectra were taken using dilute solutions in quartz cells (1 cm path length). The fluorescence profile of sensor solutions was recorded on PerkinElmer L55 Fluorescence spectrophotometer using 1 cm path length of quartz cells. Scanning electron microscopic (SEM) studies were conducted on samples obtained after drying the aqueous solutions of materials (10
Polymer dye
Initially, the solution of ZnO was synthesized by mixing the alcoholic solution of Zn(NO3)2·6H2O (595 mg, 2.0 mmol) with alcoholic solution of NaOH (120 mg, 3.0 mmol). A white product was separated out and the product was washed by ethanol. The product was dried at 150°C. Polymer dye
The polymer compounds (604 mg, 3 mmol) were taken along with RuCl3 trihydrate complex (100 mg) in dry MeOH and the solution was refluxed for 10 h. The progress of the reaction was monitored by IR and UV-Vis absorption spectroscopy by taking a small sample from the reaction mixture. Upon completion of reaction, solution was concentrated, cooled, and stirred with petroleum ether. The resultant solid was washed by dichloromethane and dried in vacuum over anhydrous calcium chloride. Polymer Schiff base showed strong absorption band in the region of 1630–1660 cm−1. However, upon complexion with the metal it shifted to lower frequency indicating formation of the metal complex with CH=N. Hence, polymer-ruthenium composite dye
For the fabrication of ZnO based DSSCs, we have prepared two different dyes: polymer dye
Assembly sections of polymer decorated ZnO based DSSC. ((A) and (B)) Polymer dye capped ZnO nanoparticles in the form of a paste on ITO conductive sheet acting as a photoanode having a surface area 1 cm × 1 cm, (C) counter electrode acting as a cathode for DSSC made from candle dust, and (D) circuit diagram of DSSC for measuring current density and open circuit voltage for DSSC.
Chemical structure of polymer dye
For measuring photovoltaic characteristics, that is, current density and photovoltage curve, an ultrafine digital multimeter was connected to the electrodes of ZnO based DSSC with variable resistances. The light intensity of simulated source used was 100 mW/cm2. This is equivalent to one sun or AM (air mass) 1.5 of photon power that is delivered to the surface area of ZnO based DSSC. The photoelectric conversion efficiency (
The surface morphology and size distribution of polymer dye capped ZnO nanoparticles were investigated by SEM (JEOL JSM-6610) operated at 15 KV. SEM image of polymer dye capped on ZnO nanoparticles appears to be homogenously arranged (as shown in Figure
SEM image of ZnO nanoparticles: (a) high magnification image of polymer decorated ZnO nanoparticles and (b) EDS spectra of polymer decorated ZnO nanoparticles.
DLS images analysis shown in Figure
DLS spectra of polymer dye capped ZnO nanoparticles.
For structural investigations of ZnO nanoparticles, XRD spectrum was collected using PANalytical X′PERT PRO diffractometer. It was operated at 45 KV and 40 mA using Ni-filtered Cu K
X-ray diffractogram of (a) uncapped ZnO nanoparticles and (b) polymer dye
The fluorescence spectra have been recorded by exciting the samples at the wavelength of 325 nm. The fluorescence spectra of three different samples A, B, and C (polymer dye
Fluorescence spectra of different samples: (A) polymer dye
The UV-visible portion depicted the significance of optoelectronic features of ZnO nanoparticles for different three samples A (diluted polymer dye
UV-visible spectra of different samples: (A) polymer dye
The current density and voltage characteristics of polymer decorated hybrid ZnO DSSCs had been recorded for different samples A, B, and C by varied external resistances under simulated sunlight illuminations or AM 1.5 solar conditions (shown in Figure
Photovoltaic performances of hybrid ZnO based dye-sensitized solar cells (DSSCs) under simulated solar illuminations (AM 1.5).
Sample name | Name of DSSC | Open circuit voltage |
Short circuit current density |
Fill factor (FF) | Thickness of photoanode layer ( |
Efficiency of DSSC ( |
---|---|---|---|---|---|---|
A | Polymer dye |
0.55 | 4.4 | 58% | 10.57 | 1.40 |
B | Polymer dye |
0.67 | 8.7 | 60% | 16.11 | 3.50 |
C | Polymer-ruthenium composite dye |
0.83 | 12.6 | 65% | 25.40 | 5.28 |
Current density and photovoltage response curves for different ZnO based DSSCs: (A) polymer dye
Comparison of thickness of photoanode and power conversion efficiency (
The highest recorded efficiency for polymer-ruthenium composite dye
The incident photon-to-current conversion efficiency (IPCE) spectra for polymer dye capped ZnO based DSSCs were measured as shown in Figure
IPCE spectra of ZnO based DSSCs for polymer dye
In this research work, we have synthesized, characterized, and evaluated the optoelectronic and photovoltaic performances of polymer decorated organic-inorganic hybrid ZnO based dye-sensitized solar cells. For evaluating the performances of the first two samples of ZnO DSSCs, we have used a capping agent 2-thiophenecarboxaldehyde (2-TPC). In the third case, polymer-ruthenium metal complex based composite dye had been prepared and was used as a good dying agent in the fabrication of ZnO DSSC. Polymer dye
The authors declare no competing financial interests.
The authors are very grateful to laboratory facilities for synthesis and measurement purposes at Punjab University, Chandigarh, and Indian Institute of Technology, Ropar, Punjab (India). The authors are also grateful to I. K. Gujral Punjab Technical University, Jalandhar, Kapurthala, for providing necessary research facilities.