Exploiting the colloidal nanocrystal library to construct electronic devices

Abstract

Synthetic methods produce libraries of colloidal nanocrystals with tunable physical properties by tailoring the nanocrystal size, shape, and composition. Here, we exploit colloidal nanocrystal diversity and design the materials, interfaces, and processes to construct all-nanocrystal electronic devices using solution-based processes. Metallic silver and semiconducting cadmium selenide nanocrystals are deposited to form high-conductivity and high-mobility thin-film electrodes and channel layers of field-effect transistors. Insulating aluminum oxide nanocrystals are assembled layer by layer with polyelectrolytes to form high-dielectric constant gate insulator layers for low-voltage device operation. Metallic indium nanocrystals are codispersed with silver nanocrystals to integrate an indium supply in the deposited electrodes that serves to passivate and dope the cadmium selenide nanocrystal channel layer. We fabricate all-nanocrystal field-effect transistors on flexible plastics with electron mobilities of 21.7 square centimeters per volt-second.

Solution-processed semiconductors for next-generation photodetectors

“…21,101 The realization of efficient all-solution-processed photodetectors is also an attractive route to be explored towards flexible and wearable photodetection. 102 In the next section we discuss novel functionalities that, enabled by the use of solution processed materials, allow the realization of single pixel multispectral narrowband photodetection as an example of where the technology may take us.…”

Engineering the surface chemistry of lead chalcogenide nanocrystal solids to enhance carrier mobility and lifetime in optoelectronic devices

“…The m and t strongly depend on the NC thin film's surface chemistry. 8,[22][23][24][25] The long length of BDT ligands creates NC thin films with relatively large interparticle distance and therefore low m and conductivity, but BDT passivates NC surface sites supporting long carrier t. 11,25 The compact SCN ligands are effective at reducing interparticle distance to yield high m thin films, but a low surface coverage of SCN ligands generates a greater concentration of surface states. A general approach to increase m is to reduce the interparticle spacing by ligand exchange.…”

Ligand-induced symmetry breaking, size and morphology in colloidal lead sulfide QDs: from classic to thiourea precursors

“…Lead chalcogenide (PbE, E = S, Se, Te) colloidal quantum dots (CQDs), exhibiting strong three-dimensional quantum confinement and ease of synthesis, are among the most investigated classes of semiconductor nanocrystals. Their possible use in optoelectronics, photodetectors, as promising thermoelectrics, electronic CMOS converters and, in particular, in solar cell devices, has engendered rapid advances in recent years [3][4][5][6][7][8][9][10]. Intense research has been addressed to optimize the synthesis in order to improve batch-to-batch reproducibility and reaction yield, while keeping or enhancing the photophysical performance.…”