Ingredients of a good scientific talk

Justin HodgkissSCPS postgraduate workshop

15 January 2013

Goal

To get the audience to appreciate your science story

What’s the story?

Be very clear in your head before making slides

DistilDistil

Distil

1 sentence?

What’s the story?

Be very clear in your head before making slides

Where are you going?

Choose structure to fit the story

Think creatively

What does audience need to know to appreciate story?

Don’t be constrained by:- Structure used by everyone else- Your previous talks- desire to include everything you know

Value the first minute

One chance to hook the audience – don’t blow it!

Must be stimulating

Get to the point

Outline• Introduction to organic solar cells

- Excitons- Charge generation

• Experimental methods- Optical Kerr gate- Transient absorption spectroscopy

• Results- Exciton dynamics- Measurement of cross-sections

• Conclusions

• Acknowledgements

Light absorption triggers a cascade if photophysical processes in OPVs

Exciton diffusion coefficients (10-3 cm2 s-1 for P3HT) only ~0.1 nm in 100 fs

Adv. Mat. 20 (18): 3516-3520

Optimized domains ~10-20 nm

100nm

Adv. Funct. Mat., 15(10): 1617-1622.

Exciton bottleneck – model must be wrong!

Free charge carrier generation within 40 fs after photoexcitation

Physical Review Letters 108(5): 056603.

Charge separation prior to exciton formation?

Delocalized excitation

Ground state

Localized exciton

Separated chargesThermalization(sub ps)

Fluorescence

hn

‘Hot CT’

Ultrafast formation of free charges

1. Charge delocalization dynamics via time resolved absorption cross-section

2. Role of the exciton via ultrafast photoluminescence

Ultrafast formation of free charges

1. Charge delocalization dynamics via time resolved absorption cross-section

Friend, R. H. et. al. Science, 2012, 335, 1340-1344.

……….. ………

Ultrafast formation of free charges

1. Charge delocalization dynamics via time resolved absorption cross-section

2. Role of the exciton via ultrafast photoluminescence

Each slide makes a point

• Clean, minimal, balanced

• Clear, relevant graphics

• Large font

Growth in charge absorption tracks PL decay

These charges are formed via bound emissive excitons

Clarity is key

• Use every means to make it EASY TO FOLLOW

–Colour coding

Light absorption triggers a cascade if photophysical processes in OPVs

Exciton diffusion coefficients (10-3 cm2 s-1 for P3HT) only ~0.1 nm in 100 fs

Adv. Mat. 20 (18): 3516-3520

Optimized domains ~10-20 nm

100nm

Adv. Funct. Mat., 15(10): 1617-1622.

Exciton bottleneck – model must be wrong!

Free charge carrier generation within 40 fs after photoexcitation

Physical Review Letters 108(5): 056603.

Clarity is key

• Use every means to make it EASY TO FOLLOW

– Colour coding

– Repeated imagery

Evidence for charge separation prior to exciton formation

Delocalized excitation

Ground state

Localized exciton

Separated chargesThermalization(sub ps)

Fluorescence

hn

‘Hot CT’

Clarity is key

• Use every means to make it EASY TO FOLLOW

– Colour coding

– Repeated imagery

– Eliminate jargon

Practice, practice, practice

• Out loud (record)

• KEEP TO TIME

• Remember:– Key point of each slide– Transitions– Crucial concepts to emphasize…. Slow down

Preparations on the day• Multiple copies (USB, dropbox, email…), + printout

• .pdf version

• Check display, animation, video’s, lighting, Mac??

• Pointer

• Timer

• Where to stand?

Relax and enjoy the moment

• Easy if you’re well prepared!

• Time flies

• Don’t panic if you forget something……. Just slow down and keep it simple

Reflect on the best and worst talks you’ve seen

… best and worst talks you’ve given?