An easy approach of preparing strongly luminescent carbon dots and their polymer based composites for enhancing solar cell efficiency

We report a one-step approach for synthesis of carbon dots (CDs) under mild conditions. By using (N-(2-aminoethyl)-3-aminopropyl)tris-(2-ethoxy) silane (KH791) as catalyzer, stabilizing and passivation agent, the resultant CDs are allowed to be self-assembled in solution and exhibit excitation wavelength independent photoluminescence (PL) performance. When the solvent is removed, luminescent CDs filled polysiloxane composite is readily yielded through hydrolytic condensation between KH791 and CDs. According to this habit, CDs can be conveniently utilized by coating the hybrid solution on proper substrates, etc. On the basis of the luminescent down-shifting behavior of the composite with CDs, power conversion efficiency of polymer-fullerene-based bulk heterojunction solar cell is increased by about 12% due to effective light conversion of near ultraviolet and blue-violet portions of sunlight. The simple preparation, easy processing and unique PL properties of CDs and their polymer composite provide the latter with broad applicability.