Exploring the Effects of Bay Position Chlorination on the Emissive Properties of Chloro-(Chloro)n-Boron Subnaphthalocyanines for Light Emission.

Abstract: It has been previously found that through an established synthesis of the macrocycle boron subnaphthalocyanine (BsubNc) that random bay-position chlorination occurs and results in a mixed alloyed composition that cannot be separated; called chloro-(chloro_n)-boron subnaphthalocyanines (Cl-Cl_nBsubNcs). Through modifications of the synthetic method, amounts of the average bay-position chlorination can be varied. Cl-Cl_nBsubNcs are fluorescent and therefore here we explore the effect of the amount of bay-position chlorination on the photoluminescent and electroluminescent properties of Cl-Cl_nBsubNcs. Distinct from previous reports detailing the positive impact of higher average bay-position chlorination, we find that the photophysical processes important to OLEDs improve with lower average bay-position chlorination. A higher degree of bay-position chlorine shows higher nonradiative recombination rates, lower photoluminescence quantum efficiencies and a basic OLEDs exhibits a greater host emission fraction, implying less effective energy transfer. These results advance the consideration of subnaphthalocyanines for light-emitting and optoelectronic applications.