Controllable Construction,Photonic Properties And Sensing Applications Of Organic Dual-color Micro/Nano-heterostructures

In recent years,organic micro/nano-heterostructures,with the excellent photoelectric properties and ease of processing are gradually studied for the construction of nano-optoelectronics devices such as micro-lasers,micro-transistors,and micro-sensors,attracting widespread attention.Compared with the traditional inorganic semiconductor heterostructures,organic micro/nano-heterostructures have some obvious advantages such as more optional materials,milder preparation conditions,wider spectral ranges,andbecome a kind of very important nanophotonic materials,possibly realizing the higher-level integrated photonic functions that single-component materials cannot achieve.However,owing to the complex synergetic interactions among two or more components,the controllable construction of various organic micro-nano heterostructures for the realization of complex integrated photonic functions still remains a great challenge.In general,the process to prepare the organic micro/nano-heterostructures lacks a rationally constructed strategy,and their functions and applications are also relatively simple,which do not exert the characteristics of the composite structures.In this paper,for the purpose of the integrated photonic functions(logical operations,multi-signal sensing),we proposed a rational assemblystrategybyco-crystallizingtoconstruct micro/nano-heterostructures,which is based on the controlled donor-acceptor interactions.Based on this strategy,the controlled preparation,optical logic operation and multi-signal sensing applications of dual-color micro/nano-heterostructures,have been systematically studied.The details are as follows:1.Organic D-A₁/D-A₂ cocrystal heterostructures:Dual-color heterostructures that dual cocrystal microwires are interconnected is constructed,using the same donor molecule(D)as a bridge.We choose a polycyclic aromatic hydrocarbon molecule as the donor(D),and two acceptor molecules(A₁,A₂)with different LUMO energy levels form two cocrystal(D-A₁,D-A₂)microwires with different luminescent colors,based on a simple and controllable charge transfer interaction between the donor and acceptor.The lateral and branching cocrystal heterostructures which use the ternary(D,A₁,A₂)liquid-phase co-crystallization strategy and utilize the hydrogen bond interactions between the cocrystals can be controllable produced by adjusting the concentration of the donor and receptor in the solution.Under the local excitation of the laser,the main D-A₁ cocrystal microwires and the branch D-A₂ cocrystal microwires in the two heterostructures show good blue and green optical waveguide performance radiation,respectively.Further,the logical devices of�OR�and�AND�were constructed respectively to realize the multifunctional application of the heterostructure by using the dual-color waveguide performance of the two heterostructures.2.Organic D₁-A/D₂-A cocrystal heterostructures:We choose an n-type semiconductor molecule as the charge transfer acceptor(A)and use two polycyclic aromatic hydrocarbon molecules with different HOMO energy levels as the charge transfer donors(D₁,D₂).Dendritic heterostructures composed of two different luminescent color cocrystal microwires(D₁-A,D₂-A)are controllable assembly by using the ternary liquid phase co-crystallization strategy.It further verifies�the ternary co-crystallization strategy to construct a dual-color heterostructure�is feasibility.Under the local excitation of the laser,the trunk junction D₁-A cocrystal exhibits a bright red fluorescent waveguide,while the branch D₂-A cocrystal exhibits a prominent blue fluorescent waveguide.The trunk and branches of the heterostructure can be excited at the same time,which can be coupled to obtain obvious white light emission.On this basis,we have further implemented complex optical logic operations.3.Dual-color electrochemiluminescent sensing with micro/nano-heterostructures:The simultaneous detection of two small biological molecules is realized by using the dual-color electrochemiluminescence property of organic dendritic heterostructures We select tris(2-phenylpyridine)iridium and fluoranthene as cation and cathode electrochemiluminescent molecules respectively.There is an interaction between the donor and acceptor molecules.The dual-color micro/nano-heterostructures with a green tris(2-phenylpyridine)iridium as the trunk and a blue fluoranthene as the branches can be controllable preparation through the�binary cooperative co-assembly�strategy.This form of dendritic heterostructures can not only stably integrate two different electrochemiluminescent molecules,but also effectively reduce the luminescence quenching caused by energy transfer between the two components.Scientific research indicates that the trunk and branches of the heterostructures can respectively perform electrochemiluminescence at the anode and cathode,which can selectively respond to the concentration change of lysine and cysteine.It further realizes the sensitive detection of two small biological molecules.