Solar cells fabrication with nanoparticles

A hybrid ink has been prepared from copper rich CuSe nanoparticles and an indium precursor solution to form CuInSe2 thin films for solar cell applications. Monoethanolamine (MEA) was used as a capping ligand that chelates with the Cu-Se nanoparticles and In precursor. Cu-rich Cu-Se nanoparticles were synthesized and subsequently washed with MEA. Resultantly, a Cu-MEA complex was formed and copper content of the nanoparticles was reduced. CuInSca thin films were deposited at 450 °C using this hybrid ink. PV devices fabricated by using these films demonstrated a power conversion efficiency of 5.04% as compared to an efficiency of 1.04% for normally synthesized copper rich CuSe nanoparticles. This observation confirmed that the Cu-MEA complex had a strong influence on the performance of CuInSc2 based solar cells produced with the hybrid ink process. 

One of the strategies is to minimize the diffusion path of exitons (botmd states between an electron and electron hole) generated by photons hitting the active material in a photovoltaic cell. Once separated, holes and electrons should reach anode and cathode electrodes, respectively. During the process, recombination of holes and electrons lead to energy losses via thermal dissipation. In order to reduce such losses, minimizing the diffusion paths of exitons by means of BCP-derived nanostructures may be beneficial. To this end, a thin solid-state dye-sensitized solar cell (ssDSSC) with a 3D gyroidal titania network was fabricated (see Fig. 12) [37]. In contrast to typical disordered nanoparticle networks, the ordered mesoporous... 

Hyun et al. [345] prepared PbS Q-dots in a suspension and tethered them to Ti02 nanoparticles with a bifunctional thiol-carboxyl linker molecule. Strong size dependence due to quantum confinement was inferred from cyclic voltammetry measurements, for the electron affinity and ionization potential of the attached Q-dots. On the basis of the measured energy levels, the authors claimed that pho-toexcited electrons should transfer efficiently from PbS into T1O2 only for dot diameters below 4.3 nm. Continuous-wave fluorescence spectra and fluorescence transients of the PbS/Ti02 assembly were consistent with electron transfer from small Q-dots. The measured charge transfer time was surprisingly slow ( 100 ns). Implications of this fact for future photovoltaics were discussed, while initial results from as-fabricated sensitized solar cells were presented. 

Highly ordered potato chip like arrays were formed with the 0.01 M and 0.03 M concentration of Inch used in the reaction whereas formation of flower shaped structures with an average diameter 3 pm was found to cover entire FTO/compact-Ti02/nanoporous-Ti02 substrate when the concentration of Inch was increased to 0.1 M (Fig. 22). The pores of nanoporous-Ti02 film were also filled by CuInS2 nanoparticles. This later film was used to fabricate a heterojunction solar cell of configuration... 

Geng X, Qi Z, Li M, Duan BK, Zhao L, Bohn PW (2012) Fabrication of antireflective layers on silicon using metal-assisted chemical etching with in situ deposition of silver nanoparticle catalysts. Solar Energy Mater Solar Cells 103 98-107... 

Solid state Dye-Sensitized Solar Cell, Fig. 3 (left) Ti02 nanoparticle mesostracture (Reproduced with permission from [46]). (right) HRTEM image of a Sn02 nanocrystal within the mesoporous films fabricated from sintered nanoparticle paste and coated with Ti02 coating fi-om a 20 mM TiCLt solution (Reprinted with permission... 

Anandan et al. reported that PVDF was used as a component in fabrication of DSCs [211]. For such a purpose, heteropolyacid was impregnated in PVDF polymer with iodine/iodide as a solid polymer electrolyte for DSCs in order to effectively decrease the back-electron transfer reaction TiOi nanoparticles were used as dye-adsorbants. The solar cell, composed of new polymer electrolyte (PVDF), Ti02 nanoparticles (photoanode) and conducting carbon cement, was cemented on conducting glass (photocathode). An overall energy conversion efficiency of up to 8% was reported [211]. 

Deka et al. reported the phosphine-free synthesis of Cu2-xSe nanocrystals by the swift injection of a Se solution in ODE into a reaction mixture composed of CuCl, OAm and ODE at 300 C. As-obtained product primarily consisted of cuboctahedral Cu2 xSe nanocrystals of ca. 16nm diameter along with small amount ca. 5%) of CuSe hexagonal platelets of approximately 100 nm which was removed by centrifugation. When the reaction was carried out at temperatures of 315 or 330 °C, a mixture of tetragonal CuSe and Cu nanoparticles were formed due to simultaneous reduction of Cu(I) salt by OAm. The Cu2-xSe NCs showed a shoulder at 480 nm and a strong peak at 1150nm attributed to direct and indirect band gap transitions. As-deposited Cu2-xSe films from the nanocrystals exhibited p-type conductivity, and are hence considered suitable for the fabrication of solar cells. 

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