Agenda Lesson Objectives Do Now Do Now Dye-Sensitized Solar Cells Extension DSSC dye discussion Lesson Objectives SWBAT compare the effectiveness of different fruit juices as dyes for DSSCs. Do Now What do you think you will observe if the dye from a different fruit does not work as well as the blackberry juice? What is an advantage of dye-sensitized solar cells over standard solar cells?

Pick either blueberries and strawberries and remake the DSSC

Anthocyanin structure Conjugated double bond system http://engineering.dartmouth.edu/reu/2006/Jensen-Report.pdf

Anthocyanins are pigments that produce many of the colors we see Cherries Eggplants Red cabbage (has over 30 types of anthocyanins!)

Pigments in blackberries

What if you just used one of the pigments in blackberries as the dye for a DSSC?

Hydrangeas Contains anthocyanins Color dependent on the soil pH Acidic soil – blue flowers Basic soil – pink/red Slightly acidic/neutral – purple or a mix of blue and pink Depends on species of hydrangea In strongly acid soil (pH below 6), flowers turn blue. In alkaline soil (pH above 7), flowers turn pink or even red. In slightly acid or neutral soil (pH 6 to 7), blooms may be purple or a mix of blue and pink on a single shrub. Keep in mind that selections vary in their sensitivity to pH. For example, 'Ami Pasquier' stays crimson in all but the most acid soil and 'Purple Tiers' remains purple.

Post Lab Questions 1.  What differences did you observe between the blackberry cell you made yesterday and today's cell? 2.  Why are blackberries an effective source of dye?  What are the essential chemical features of an effective dye? 3.  Do you think apples or raspberries would be more likely to work as a source of dye for solar cells?