Mercaptophosphonic acids as efficient linkers in quantum dot sensitized solar cells

Abstract

New mercaptophosphonic linkers are presented for the attachment of ternary quantum dots to ZnO and TiO2 for photovoltaic applications.

Efficient eco-friendly inverted quantum dot sensitized solar cells

“…This results in the k HT values in the range from 4 × 10 7 to 8 × 10 8 s –1 , which means that the hole transfer in the studied inverted systems NiO/QD is fast and comparable to previously observed electron transfer rates ( k ET = 10 7 s –1 ) in “classical” systems, such as TiO 2 /CuInS 2 . 42 , 51 , 53 At the same time, as mentioned before the hole transfer to the electrolyte is much slower in classical systems with k HT of 2–3 orders of magnitude lower compared to k ET . 10 , 54 Very few data is available on hole transfer to NiO in the inverted sensitized systems with two recent works reporting on the hole transfer from CdSe to NiO with the rates in the range of 10 8 to 10 9 s –1 , 29 , 30 which are close to the ones observed in this work.…”

“…4b and its slope is equal to the rate of quenching. 42 , 52 The equivalent graphs for CuInS x Se 2– x :Cd 2+ , CuInS 2 :Zn 2+ and CuInS 2 :Cd 2+ are given in ESI. † We fit the ln(PL ratio) to a sum of three-exponentials before differentiation and obtain the hole transfer rate from …”

“…An obvious disadvantage of this type of sensitizers is the toxicity of cadmium compounds whose use should be avoided. Recently, a series of important research works have reported the successful use of colloidal ternary or quaternary QDs for solar cells, 6 , 38 – 42 such as CuInS 2 , CuInSe 2 , AgInS 2 which are non-toxic as they do not contain heavy metals, have high absorption coefficients, long photoluminescence lifetimes and band gaps (1–1.5 eV) adapted for efficient sunlight harvesting. 43 Moreover, due to crystalline flexibility and defect tolerance such QDs offer alternative band gap tuning strategies in addition to the classical size control: a mixture of the chalcogenide atoms (S 2– , Se 2– ) and introduction of new cations (Zn 2+ , Ga 3+ ) into the ternary crystalline structure allows varying the band gap in a wide range.…”

Hydrothermal Synthesis of Aqueous-Soluble Copper Indium Sulfide Nanocrystals and Their Use in Quantum Dot Sensitized Solar Cells

“…However, the observed photovoltaic performances ( Figure S11 , Table S8 ) were much lower, compared to TiO 2 . Judging from the coloration of the electrode, this is probably a consequence of lower NC loading compared to similar systems using ZnO nanowires sensitized with CIS NCs prepared in organic phase [ 53 ]. Despite the lower efficiencies, the general trend observed for mesoporous TiO 2 sensitized electrodes is also valid for ZnO nanowires: the efficiencies of the fractionated CIS NCs are lower than those of the unpurified samples, mainly due to a much lower photocurrent.…”

Correlating photovoltaic properties of a PTB7-Th:PC71BM blend to photophysics and microstructure as a function of thermal annealing

“…The PL decays of blend films in both cases are faster compared to decays of their corresponding neat films and this is likely due to charge transfer or resonant energy transfer between the well intermixed donor and acceptor molecules in the blend. We extracted quenching efficiency using the previously reported fitting approach 33,38 ࣘ ൌ െ ‫‬ ‫‬…”