Molecular‐Level Switching of Polymer/Nanocrystal Non‐Covalent Interactions and Application in Hybrid Solar Cells

Abstract

Abstract.Hybrid composites obtained upon blending conjugated polymers and colloidal semiconductor nanocrystals are regarded as attractive photoactive materials for optoelectronic applications.Here we demonstrate that tailoring nanocrystal surface chemistry permits to control noncovalent and electronic interactions between organic and inorganic components. We show that the pending moieties of organic ligands at the nanocrystal surface do not merely confer colloidal stability while hindering charge separation and transport, but drastically impact morphology of hybrid composites during formation from blend solutions. The relevance of our approach to photovoltaic applications is demonstrated for composites based on poly(3-hexylthiophene) and lead sulfide nanocrystals, considered as inadequate until this report, which enable the fabrication of hybrid solar cells displaying a power conversion efficiency that reaches 3 %. By investigating (quasi)steady-state and time-resolved photo-induced processes in the nanocomposites and their constituents, we ascertain that electron transfer occurs at the hybrid interface yielding long-lived separated charge carriers, whereas interfacial hole transfer appears hindered. Here we provide a reliable alternative aiming to gain control over macroscopic optoelectronic properties of polymer/nanocrystal composites by mediating their non-covalent interactions via ligands' pending moieties, thus opening new possibilities towards efficient solution-processed hybrid solar cells.3

Conjugated polymer P3HT–Au hybrid nanostructures for enhancing photocatalytic activity

“…For example, hyper-efficient energy transfer from a conjugated polymer to gold NPs has been described by Fan et al 9 Warner et al enlisted the energy transfer phenomenon occurring from MEH-PPV to PbS nanocrystals. [12][13][14][15][16][17][18][19] A hybrid system composed of p-conjugated polymers and inorganic nanoparticles (NPs) remains a frontier area of research, [20][21][22] because the organic part possesses a significantly large absorption cross-section due to delocalized p-electron transition from the ground state (S 0 ) to the excited state (S n ) and the inorganic part exhibits unique optical properties due to quantum confinement. 11 Extensive studies have been persuaded to understand the electron transfer/ charge transfer dynamics in inorganic/organic hybrid systems.…”

Role of Polymer in Hybrid Polymer/PbS Quantum Dot Solar Cells

“…14 The arenethiolate-capped PbS QDs, prepared by surface modification of the assynthesized PbS QDs with p-methylbenzenethiolate, display good long-term colloidal stability and retain their peculiar cubic close-packing self-assembly in HCs comprising polymers with aliphatic side chains, thus leading to ideal nanometer scale phase separation and comparable morphologies in several HCs. 15 In this study, we thus take advantage of such an optimized and stable HC morphology to pursue the description and explanation of conjugated polymer contribution to photocurrent generation mechanisms in HC-based solar cells. Notably, our findings suggest 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 unexpected guidelines for polymer selection, which are obtained by comparing the opto-electronic properties and photovoltaic behavior of HCs comprising five organic semiconductor polymers.…”

A probabilistic model of the electron transport in films of nanocrystals arranged in a cubic lattice

“…Moreover, a further analysis could include the charge transport in more complicated systems, as for example NC-polymer heterojunctions [8]. [14]) and simulations (red squares with full line).…”

“…However, charge carrier mobility among NCs is also very important in NC-polymer or NC-molecule hybrid films, which are employed in hybrid solar cells, as in Giansante et al [8] and Mastria et al [9].…”