First row transition metals decorated boron phosphide nanoclusters as nonlinear optical materials with high thermodynamic stability and enhanced electronic properties; A detailed quantum chemical study

•Surface doping on boron phosphide (B12P12) nanocage with first row transition metals is investigated.•Interaction of transition metals with the cage appreciably reduced the H-Lgap.•Linking transition metals brings significant enhancement in the NLO response of the boron phosphide nanocage.•Significant second harmonic generation efficiency is observed at routinely used laser wavelengths.