Originally Posted by Struan Gray
If P.E. is thinking of the same French work that I am, the work was published in Nature, which unlike most scientific journals is still quite easy to track down.
"Enhanced yield of photoinduced electrons in doped silver halide crystals"
Jaqueline Belloni et al.
Nature vol 402, pp 865-867 (1999).
Struan, that is it. There is also a web page with the information.