Designing different nanomaterials with new and useful properties required for developing day-to-day technologies has remained in the forefront of research for decades. Among these, semiconducting, light-emitting, plasmonic, photovoltaic, and magnetic properties are in the frontline. [1][2][3][4][5][6][7][8][9][10][11][12][13] Furthermore, materials with rectification properties remain one of the most demanding materials in recent times. [1][2][3][4][14][15][16][17] Very recently, semiconducting nanomaterials with tunable plasmonic absorption properties have also been reported; [5][6][7][8][18][19][20][21][22] these may further expand the already widespread applications of these nanomaterials in diverse research fields, including both in biology and device-based technologies. Hence, materials with several of these new properties are in demand for their implementation in different developing modern technologies.For designing nanomaterials, the colloidal synthetic method has remained unique and unbeatable to date. However, the classical mechanistic approach for fabricating these materials following this solution phase synthesis is more effective for tuning over a smaller range of dimensions, and produces mostly smaller-sized nanocrystals. Efforts to get larger-sized nanocrystals lead either to a wider size distribution or precipitation. Generally, this has been observed for 0D, 1D, or 2D crystal-growth processes. [23][24][25][26][27][28][29][30] Hence, designing of surface-ligand-capped nanomaterials with a wide range of size tunability that maintains their narrow size distribution throughout still remains challenging and requires more advanced synthetic methods.Confining the growth to 2D, we explore here the fabrication of nano-to microscale-tunable platelet-shaped Cu I phosphide as one of the upcoming materials associated with several new properties. This shows the band-edge absorption in the NIR spectral window, tunable surface plasmonic absorption in mid-IR window and also has the rectification properties required for possible exploration as photovoltaic material. Synthesis with such a wide tunable size range (ca. 1000 nm) has been performed by controlling the number of nucleations followed by rapid growth along two feasible directions. In the entire tunable regime, the size distribution remains narrow; the platelets maintain a hexagonal shape and retain single crystallinity. Moreover, unlike reported nanoplatelets made from various materials, these show several intriguing patterns of MoirØ fringes in their overlapping regions on the TEM grid. Finally, these p-type semiconducting platelets are explored to study their, photocurrent, photoresponse and photovoltaic activity under whitelight illumination.For the synthesis of copper phosphide, phosphine gas generated ex situ [31] has been explored as the phosphide source. This also helps to carry out the reaction at relatively moderate temperatures (200-230 8C). Using CuCl as Cu precursor, a mixture of alkylamine and trioctylphosphineoxide as solvent, and trioctylpho...

Multinary nanocrystals (CuInS2, CIS, and AgInS2, AIS) are widely known for their strong defect state emission. On alloying with Zn (CIZS and AIZS), stable and intense emission tunable in visible and NIR windows has already been achieved. In these nanocrystals, the photogenerated hole efficiently moves to the defect-induced state and recombines with the electron in the conduction band. As a result, the defect state emission is predominantly observed without any band edge excitonic emission. Herein, we report the doping of the transition-metal ion Mn in these nanocrystals, which in certain compositions of the host nanocrystals quenches this strong defect state emission and predominantly shows the spin-flip Mn emission. Though several Mn-doped semiconductor nanocrystals are reported in the literature, these nanocrystals are of its first kind that can be excited in the visible window, do not contain the toxic element Cd, and provide efficient emission. Hence, when Mn emission is required, these multinary nanocrystals can be the ideal versatile materials for widespread technological applications.

Engineering the surface energy through careful manipulation of the surface chemistry is a convenient approach to control quantum confinement and structure dimensionality during nanocrystal growth. Here, we demonstrate that the introduction of pyridine during the synthesis of methylammonium lead bromide (MAPbBr3) perovskite nanocrystals can transform three-dimensional (3D) cubes into two-dimensional (2D) nanostructures. Density functional theory (DFT) calculations show that pyridine preferentially binds to Pb atoms terminating the surface, driving the selective 2D growth of the nanostructures. These 2D nanostructures exhibit strong quantum confinement effects, high photoluminescence quantum yields in the visible spectral range, and efficient charge transfer to molecular acceptors. These qualities indicate the suitability of the synthesized 2D nanostructures for a wide range of optoelectronic applications.

Au-Bi2S3 heteronanostructure photocatalysts were designed in which the coupling of a metal plasmon and a semiconductor exciton aids the absorption of solar light, enhances charge separation, and results in improved catalytic activity. Furthermore, these nanostructures show a unique pattern of structural combination, with Au nanoparticles positioned at the center of Bi2S3 nanorods. The chemistry of formation of these nanostructures, their epitaxy at the junction, and their photoconductance were studied, as well as their photoresponse properties.

Here we report that mesoporous ternary oxide Zn2SnO4 can significantly promotes the crystallization of hybrid perovskite layers and serves as an efficient electron transporting material in perovskite solar cells. Such devices exhibit an energy conversion efficiency of 13.34%, which is even higher than that achieved with the commonly used TiO2 in the similar experimental conditions (9.1%). Simple one-step spin coating of CH3NH3PbI3-xClx on Zn2SnO4 is found to lead to rapidly crystallized bilayer perovskite structure without any solvent engineering. Furthermore, ultrafast transient absorption measurement reveals efficient charge transfer at the Zn2SnO4/perovskite interface. Most importantly, solar cells with Zn2SnO4 as the electron-transporting material exhibit negligible electrical hysteresis and exceptionally high stability without encapsulation for over one month. Besides underscoring Zn2SnO4 as a highly promising electron transporting material for perovskite solar cells, our results demonstrate the significant role of interfaces on improving the perovskite crystallization and photovoltaic performance.