The effect of amorphous TiO₂ in P25 on dye-sensitized solar cell performance

Abstract

P25 is one of the most widely used forms of titanium(iv) oxide (TiO), routinely utilised in dye-sensitised solar cells (DSCs), where it is often employed as a control, in spite of its poorly defined nature and the typically low device efficiency (or possibly because of this). Work by Park in 2000 and later by Lin et al. suggests that the rutile component might not be to blame for this, as has often been claimed. Recently it has been observed that P25 has quite a sizable amorphous content. A method to selectively remove this non-crystalline material has been developed, allowing for scrutiny of the role this amorphous material plays. Here we compare hydrothermally treated P25 (H-P25) with the as-received material, realizing solar-to-electric conversion efficiencies of 5.3% and 3.2% respectively. More importantly, this reveals important information about the detrimental effect of amorphous TiO on DSC performance, with broader implications, as most researchers do not actively examine their synthesized materials for the presence of an amorphous component.

A Comparative Study of TiO2 Paste Preparation Methods Using Solvothermally Synthesised Anatase Nanoparticles in Dye-Sensitised Solar Cells

“…The SANP-S sample showed slightly narrower peaks, implying slightly higher crystallinity due to the additional sintering time. Previously, we demonstrated the role amorphous content plays on DSC performance, as a result of decreased charge injection efficiency [18]. Preliminary measurements showed the amorphous content to be quite low in these materials (only a few percent at most; data to be published elsewhere [26]), indicating that this would not be a major factor affecting the charge injection efficiency.…”

“…This was then redispersed in ethanol, while SANP-T was maintained in ethanol. The dispersions were combined with terpineol (Alfa Aesar, U.S.A) and ethyl cellulose (Sigma, U.S.A) to create pastes similar to those in our previous reports [15,18,27]. These pastes were then screen-printed onto substrates and calcined following a multi-step program up to 500 °C.…”

“…A large portion of work published on DSC development (~40%, which equates to more than 1200 publications) has been on the synthesis and/or modification of metal oxides, mostly TiO 2 , as efficient photoanode materials [17]. The vast majority of synthesised TiO 2 nanoparticles in these reports were dried, calcined and then re-dispersed to make a printable paste [14,18,19]. While a handful of exceptions exists where the nanoparticles were kept in suspension after their synthesis [7,10,11], producing a transparent film due to the high nanoparticle dispersion.…”

Produção de Componentes de Células Fotovoltaicas Sensibilizadas de Baixo Custo de 3ª Geração

“…Com a finalidade de aumentar a absorção espectral de TiO 2 na região visível, é utilizada então a sua dopagem com um sensibilizador. Em que, o sensibilizador aumenta o caminho óptico da camada e resulta na conversão da energia luminosa em eletricidade através do evento de transferência de elétrons entre o corante (sensibilizador) e o óxido metálico, transformando-se em células solares com alta eficiência de geração de fotocorrente [13][14][15] . As atuais DSSCs apresentam na composição do sensibilizador, metais pesados a base de complexos bipiridínicos de Ru II, que são poluentes ao meio ambiente e de alto custo.…”

Mesoporous Carbons Templated by PEO‐PCL Block Copolymers as Electrode Materials for Supercapacitors

“…Many studies at present are focused on electrode materials for energy storaged evices, including fuel cells, [1,2] solar cells, [3][4][5] lead-acid batteries, [6,7] lithium-ion batteries, [8][9][10] and supercapacitors. [11][12][13][14] Supercapacitors, especially those for electrochemical double-layerc apacitors (EDLCs), are receiving much attention for their high power densities, environmentally friendly compositions, and high cycle life.…”