In this work, excitation power-dependent infrared photoluminescence (PL) measurements were carried out on four GaSb_0.93Bi_0.07/GaSb single quantum well (SQW) samples with different in-well δ-doping density as well as the corresponding reference SQW samples without doping. PL integral-intensity evolutions of the GaSbBi SQW and the GaSb barrier/substrate show a significant decrease in the infrared emission efficiency caused by the in-well δ-doping. The doping-induced relative decrease rate is about $\mathrm{33}\mathrm{\%}-\mathrm{75}\mathrm{\%}$. Further analysis indicates that the reduction of the infrared emission efficiency is a co-consequence of the "electron loss" caused by the interfacial deterioration and the "photon loss" caused by the GaSbBi lattice quality deterioration. This work may be helpful in optimizing the performance of diluted Bi infrared light-emitting devices.