That is a nice project. I just make some clarifications for the context that you posted. There are two types of solar bottle bulbs: one (named A) is only used in daytime, and the other (named B) is used in nighttime.
For The A type (only used in daytime): the main materials to create it are a used water bottle, bleach and clean water, with bleach being only used to retard the growth of algae in the water ( the reference link: http://www.dailymail.co.uk/sciencetech/article-2393454/Brazilian-mechanic-uses-plastic-water-bottles-bleach-create-LIGHT--illuminating-1million-homes.html). People usually put A on the roof so that when the light outside runs into the water of the bottle, it will be refracted , and then spread everywhere in the house (the reference link: http://physicsbuzz.physicscentral.com/2011/09/solar-bottle-superhero.html). Hence, A is installed in the roof of the house which hardly has windows and lives in darkness during daytime. (if you look at the picture number 07 you posted above, you can recognize that it is the morning as you can see the light from the windows)
for the B type (used in the evenings): the type B is the Bulb on the fist picture you posted above, it can be used in the evenings as the bulb is connected with small solar panels which produce electricity. (the reference link: http://literoflight.org/the-night-light-project/?jfb1=3#jfbalbum1).
It is an excellent idea. Although people in urban slums are not fully aware of climate change, they have witnessed how climate has changed over the years since they were young or how it is different from the past and so affects their live. Therefore, to help them recognize impact of climate change and deeply understand the content of the exhibition rather than theory, I think during or after the exhibition, encouraging them tell or share their own stories about climate change that they has witnessed as well as how it has impacted their live with others is a further effective activity.