The characterization of germanium p—n junction detectors for use in nanosecond time-resolved near-IR-spectroscopic studies: the photosensitized formation of singlet molecular oxygen ( 1Δ g) in solution

Abstract

A nanosecond time-resolved near-IR spectrometer has been constructed for the purpose of resolving events that result in the solution-phase, photosensitized formation of singlet molecular oxygen (O 2( 1Δ g)). A germanium p—n junction detector is used to monitor the 1270 nm phosphorescence of O 2( 1Δ g). The response of several commercially available germanium detectors to pulsed radiation has been studied. The time dependence of the observed photocurrent is discussed in terms of semiconductor charge carrier dynamics. The detector response is represented in a general functional form which can subsequently be used in a deconvolution routine to extract information on the rate of O 2( 1Δ g) formation.