The underlying power of "interplay of forces" in controlling the properties and functions at the nanoscale is highlighted in this perspective. This interplay is achieved by installing attractive and repulsive forces, via proper ligand chemistry, which will guide the nanomaterials to interact with their surroundings as per the need. Along with improving the existing properties, the balancing of attractive and repulsive forces holds the prospects of imparting newer functions as well. The concept of "ligand-directed interplay of forces" is extensively practiced by our group and others for addressing many challenges in the areas of self-assembly, catalysis, light harvesting, and nanomedicine. The journey has been rewarding so far in terms of achieving many important feats in nanoscience, such as selfassembly under equilibrium and nonequilibrium regimes, outplaying ligand poisoning in nanocatalysis, channelizing the flow of energy and electron in donor−acceptor systems, multicolor photopatterning using a single nanohybrid system, biospecific targeting and therapy, and so on. As evident from this perspective, the diversity of the areas benefited showcases the breadth and depth of the impact that surface ligands and interplay of forces can have in material science. Furthermore, the implementation of the "ligand of choice" approach is one way to realize distinct and specific functions from a limited set of nanomaterials. All the examples of "liganddirected studies" mentioned in this perspective are based on the regulation of, primarily, electrostatic forces emanating from the charged surface ligands. Thus, it will be logical to try various combinations of ligands and forces, which means that the area of "ligand-directed nanochemistry" will keep on advancing beyond our predictions. Looking forward, there is plenty of room at the NP surface.

Ability to create high-contrast multicolor luminescent patterns is essential to realize the full potential of quantum dots (QDs) in display technologies. The idea of using a nonemissive state is adopted in the present work to enhance the color-contrast of QD-based photopatterns. This is achieved at a multicolor level by the photoregulation of electron and energy transfer processes in a single QD nanohybrid film, composed of one QD donor and two dye acceptors. The dominance of photoinduced electron transfer over the energy transfer process generates a nonluminescent QD nanohybrid film, which provides the black background for multicolor patterning. The superior photostability of QDs over dyes is used for the photoregulation of electron and energy transfer processes. Selective photodegradation of electron acceptor dye triggered the onset of the energy transfer process, thereby imparting a luminescent color to the QD nanohybrid film. Further, a controlled photoregulation of energy transfer process paved the way for multicolor patterning.

Diligent utilisation of sunlight by green plants has essentially paved the way for the existence of life on earth. Our understanding of the natural photosynthetic machinery reveals that an assembly...

Demonstration of fundamental photophysical properties in environmentally friendly quantum dots (QDs) is essential to realize their practical use in various light harvesting applications. We accomplish here an efficient light induced resonance energy transfer in all-QD based donor−acceptor system in water, deprived of any commonly used organic dye component. Our nanohybrid system comprises surface engineered indium phosphide/zinc sulfide (InP/ZnS) QD as the donor, and copper indium sulfide/zinc sulfide (CIS/ZnS) QD as the acceptor. The electrostatic attraction between oppositely charged QDs is vital in achieving a strong ground state complexation in the [−] InP/ZnS:::[+] CIS/ZnS QD nanohybrid. A nonlinear Stern−Volmer plot confirms the involvement of both static and dynamic components in the PL quenching of InP/ZnS QD by CIS/ZnS QD. Moreover, a temporal evolution of resonance energy transfer is realized in the solid state as well, which can improve the potential of such "all-green QD" based nanohybrid systems for device level studies.

Development of stable blue-emitting materials has always been a challenging task because of the necessity of high crystal quality and good optical properties. We have developed a highly efficient blue-emitter,...